Actual source code: vector.c

      1: /*
      2:      Provides the interface functions for vector operations that do NOT have PetscScalar/PetscReal in the signature
      3:    These are the vector functions the user calls.
      4: */
      5: #include <petsc/private/vecimpl.h>
      6: #include <petsc/private/deviceimpl.h>

      8: /* Logging support */
      9: PetscClassId  VEC_CLASSID;
     10: PetscLogEvent VEC_View, VEC_Max, VEC_Min, VEC_Dot, VEC_MDot, VEC_TDot;
     11: PetscLogEvent VEC_Norm, VEC_Normalize, VEC_Scale, VEC_Shift, VEC_Copy, VEC_Set, VEC_AXPY, VEC_AYPX, VEC_WAXPY;
     12: PetscLogEvent VEC_MTDot, VEC_MAXPY, VEC_Swap, VEC_AssemblyBegin, VEC_ScatterBegin, VEC_ScatterEnd;
     13: PetscLogEvent VEC_AssemblyEnd, VEC_PointwiseMult, VEC_PointwiseDivide, VEC_Reciprocal, VEC_SetValues, VEC_Load, VEC_SetPreallocateCOO, VEC_SetValuesCOO;
     14: PetscLogEvent VEC_SetRandom, VEC_ReduceArithmetic, VEC_ReduceCommunication, VEC_ReduceBegin, VEC_ReduceEnd, VEC_Ops;
     15: PetscLogEvent VEC_DotNorm2, VEC_AXPBYPCZ;
     16: PetscLogEvent VEC_ViennaCLCopyFromGPU, VEC_ViennaCLCopyToGPU;
     17: PetscLogEvent VEC_CUDACopyFromGPU, VEC_CUDACopyToGPU;
     18: PetscLogEvent VEC_HIPCopyFromGPU, VEC_HIPCopyToGPU;

     20: /*@
     21:   VecStashGetInfo - Gets how many values are currently in the vector stash, i.e. need
     22:   to be communicated to other processors during the `VecAssemblyBegin()`/`VecAssemblyEnd()` process

     24:   Not Collective

     26:   Input Parameter:
     27: . vec - the vector

     29:   Output Parameters:
     30: + nstash    - the size of the stash
     31: . reallocs  - the number of additional mallocs incurred in building the stash
     32: . bnstash   - the size of the block stash
     33: - breallocs - the number of additional mallocs incurred in building the block stash (from `VecSetValuesBlocked()`)

     35:   Level: advanced

     37: .seealso: [](ch_vectors), `Vec`, `VecAssemblyBegin()`, `VecAssemblyEnd()`, `VecStashSetInitialSize()`, `VecStashView()`
     38: @*/
     39: PetscErrorCode VecStashGetInfo(Vec vec, PetscInt *nstash, PetscInt *reallocs, PetscInt *bnstash, PetscInt *breallocs)
     40: {
     41:   PetscFunctionBegin;
     42:   PetscCall(VecStashGetInfo_Private(&vec->stash, nstash, reallocs));
     43:   PetscCall(VecStashGetInfo_Private(&vec->bstash, bnstash, breallocs));
     44:   PetscFunctionReturn(PETSC_SUCCESS);
     45: }

     47: /*@
     48:   VecSetLocalToGlobalMapping - Sets a local numbering to global numbering used
     49:   by the routine `VecSetValuesLocal()` to allow users to insert vector entries
     50:   using a local (per-processor) numbering.

     52:   Logically Collective

     54:   Input Parameters:
     55: + x       - vector
     56: - mapping - mapping created with `ISLocalToGlobalMappingCreate()` or `ISLocalToGlobalMappingCreateIS()`

     58:   Level: intermediate

     60:   Notes:
     61:   All vectors obtained with `VecDuplicate()` from this vector inherit the same mapping.

     63:   Vectors obtained with `DMCreateGlobaVector()` will often have this attribute attached to the vector so this call is not needed

     65: .seealso: [](ch_vectors), `Vec`, `VecAssemblyBegin()`, `VecAssemblyEnd()`, `VecSetValues()`, `VecSetValuesLocal()`,
     66:            `VecGetLocalToGlobalMapping()`, `VecSetValuesBlockedLocal()`
     67: @*/
     68: PetscErrorCode VecSetLocalToGlobalMapping(Vec x, ISLocalToGlobalMapping mapping)
     69: {
     70:   PetscFunctionBegin;
     73:   if (x->ops->setlocaltoglobalmapping) PetscUseTypeMethod(x, setlocaltoglobalmapping, mapping);
     74:   else PetscCall(PetscLayoutSetISLocalToGlobalMapping(x->map, mapping));
     75:   PetscFunctionReturn(PETSC_SUCCESS);
     76: }

     78: /*@
     79:   VecGetLocalToGlobalMapping - Gets the local-to-global numbering set by `VecSetLocalToGlobalMapping()`

     81:   Not Collective

     83:   Input Parameter:
     84: . X - the vector

     86:   Output Parameter:
     87: . mapping - the mapping

     89:   Level: advanced

     91: .seealso: [](ch_vectors), `Vec`, `VecSetValuesLocal()`, `VecSetLocalToGlobalMapping()`
     92: @*/
     93: PetscErrorCode VecGetLocalToGlobalMapping(Vec X, ISLocalToGlobalMapping *mapping)
     94: {
     95:   PetscFunctionBegin;
     98:   PetscAssertPointer(mapping, 2);
     99:   if (X->ops->getlocaltoglobalmapping) PetscUseTypeMethod(X, getlocaltoglobalmapping, mapping);
    100:   else *mapping = X->map->mapping;
    101:   PetscFunctionReturn(PETSC_SUCCESS);
    102: }

    104: /*@
    105:   VecAssemblyBegin - Begins assembling the vector; that is ensuring all the vector's entries are stored on the correct MPI process. This routine should
    106:   be called after completing all calls to `VecSetValues()`.

    108:   Collective

    110:   Input Parameter:
    111: . vec - the vector

    113:   Level: beginner

    115: .seealso: [](ch_vectors), `Vec`, `VecAssemblyEnd()`, `VecSetValues()`
    116: @*/
    117: PetscErrorCode VecAssemblyBegin(Vec vec)
    118: {
    119:   PetscFunctionBegin;
    122:   PetscCall(VecStashViewFromOptions(vec, NULL, "-vec_view_stash"));
    123:   PetscCall(PetscLogEventBegin(VEC_AssemblyBegin, vec, 0, 0, 0));
    124:   PetscTryTypeMethod(vec, assemblybegin);
    125:   PetscCall(PetscLogEventEnd(VEC_AssemblyBegin, vec, 0, 0, 0));
    126:   PetscCall(PetscObjectStateIncrease((PetscObject)vec));
    127:   PetscFunctionReturn(PETSC_SUCCESS);
    128: }

    130: /*@
    131:   VecAssemblyEnd - Completes assembling the vector.  This routine should be called after `VecAssemblyBegin()`.

    133:   Collective

    135:   Input Parameter:
    136: . vec - the vector

    138:   Options Database Keys:
    139: + -vec_view                 - Prints vector in `PETSC_VIEWER_DEFAULT` format
    140: . -vec_view ::ascii_matlab  - Prints vector in `PETSC_VIEWER_ASCII_MATLAB` format to stdout
    141: . -vec_view matlab:filename - Prints vector in MATLAB .mat file to filename (requires PETSc configured with --with-matlab)
    142: . -vec_view draw            - Activates vector viewing using drawing tools
    143: . -display name             - Sets display name (default is host)
    144: . -draw_pause sec           - Sets number of seconds to pause after display
    145: - -vec_view socket          - Activates vector viewing using a socket

    147:   Level: beginner

    149: .seealso: [](ch_vectors), `Vec`, `VecAssemblyBegin()`, `VecSetValues()`
    150: @*/
    151: PetscErrorCode VecAssemblyEnd(Vec vec)
    152: {
    153:   PetscFunctionBegin;
    155:   PetscCall(PetscLogEventBegin(VEC_AssemblyEnd, vec, 0, 0, 0));
    157:   PetscTryTypeMethod(vec, assemblyend);
    158:   PetscCall(PetscLogEventEnd(VEC_AssemblyEnd, vec, 0, 0, 0));
    159:   PetscCall(VecViewFromOptions(vec, NULL, "-vec_view"));
    160:   PetscFunctionReturn(PETSC_SUCCESS);
    161: }

    163: /*@
    164:   VecSetPreallocationCOO - set preallocation for a vector using a coordinate format of the entries with global indices

    166:   Collective

    168:   Input Parameters:
    169: + x     - vector being preallocated
    170: . ncoo  - number of entries
    171: - coo_i - entry indices

    173:   Level: beginner

    175:   Notes:
    176:   This and `VecSetValuesCOO()` provide an alternative API to using `VecSetValues()` to provide vector values.

    178:   This API is particularly efficient for use on GPUs.

    180:   Entries can be repeated, see `VecSetValuesCOO()`. Negative indices are not allowed unless vector option `VEC_IGNORE_NEGATIVE_INDICES` is set,
    181:   in which case they, along with the corresponding entries in `VecSetValuesCOO()`, are ignored. If vector option `VEC_NO_OFF_PROC_ENTRIES` is set,
    182:   remote entries are ignored, otherwise, they will be properly added or inserted to the vector.

    184:   The array coo_i[] may be freed immediately after calling this function.

    186: .seealso: [](ch_vectors), `Vec`, `VecSetValuesCOO()`, `VecSetPreallocationCOOLocal()`
    187: @*/
    188: PetscErrorCode VecSetPreallocationCOO(Vec x, PetscCount ncoo, const PetscInt coo_i[])
    189: {
    190:   PetscFunctionBegin;
    193:   if (ncoo) PetscAssertPointer(coo_i, 3);
    194:   PetscCall(PetscLogEventBegin(VEC_SetPreallocateCOO, x, 0, 0, 0));
    195:   PetscCall(PetscLayoutSetUp(x->map));
    196:   if (x->ops->setpreallocationcoo) {
    197:     PetscUseTypeMethod(x, setpreallocationcoo, ncoo, coo_i);
    198:   } else {
    199:     PetscInt ncoo_i;
    200:     IS       is_coo_i;

    202:     PetscCall(PetscIntCast(ncoo, &ncoo_i));
    203:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, ncoo_i, coo_i, PETSC_COPY_VALUES, &is_coo_i));
    204:     PetscCall(PetscObjectCompose((PetscObject)x, "__PETSc_coo_i", (PetscObject)is_coo_i));
    205:     PetscCall(ISDestroy(&is_coo_i));
    206:   }
    207:   PetscCall(PetscLogEventEnd(VEC_SetPreallocateCOO, x, 0, 0, 0));
    208:   PetscFunctionReturn(PETSC_SUCCESS);
    209: }

    211: /*@
    212:   VecSetPreallocationCOOLocal - set preallocation for vectors using a coordinate format of the entries with local indices

    214:   Collective

    216:   Input Parameters:
    217: + x     - vector being preallocated
    218: . ncoo  - number of entries
    219: - coo_i - row indices (local numbering; may be modified)

    221:   Level: beginner

    223:   Notes:
    224:   This and `VecSetValuesCOO()` provide an alternative API to using `VecSetValuesLocal()` to provide vector values.

    226:   This API is particularly efficient for use on GPUs.

    228:   The local indices are translated using the local to global mapping, thus `VecSetLocalToGlobalMapping()` must have been
    229:   called prior to this function.

    231:   The indices coo_i may be modified within this function. They might be translated to corresponding global
    232:   indices, but the caller should not rely on them having any specific value after this function returns. The arrays
    233:   can be freed or reused immediately after this function returns.

    235:   Entries can be repeated. Negative indices and remote indices might be allowed. see `VecSetPreallocationCOO()`.

    237: .seealso: [](ch_vectors), `Vec`, `VecSetPreallocationCOO()`, `VecSetValuesCOO()`
    238: @*/
    239: PetscErrorCode VecSetPreallocationCOOLocal(Vec x, PetscCount ncoo, PetscInt coo_i[])
    240: {
    241:   PetscInt               ncoo_i;
    242:   ISLocalToGlobalMapping ltog;

    244:   PetscFunctionBegin;
    247:   if (ncoo) PetscAssertPointer(coo_i, 3);
    248:   PetscCall(PetscIntCast(ncoo, &ncoo_i));
    249:   PetscCall(PetscLayoutSetUp(x->map));
    250:   PetscCall(VecGetLocalToGlobalMapping(x, &ltog));
    251:   if (ltog) PetscCall(ISLocalToGlobalMappingApply(ltog, ncoo_i, coo_i, coo_i));
    252:   PetscCall(VecSetPreallocationCOO(x, ncoo, coo_i));
    253:   PetscFunctionReturn(PETSC_SUCCESS);
    254: }

    256: /*@
    257:   VecSetValuesCOO - set values at once in a vector preallocated using `VecSetPreallocationCOO()`

    259:   Collective

    261:   Input Parameters:
    262: + x     - vector being set
    263: . coo_v - the value array
    264: - imode - the insert mode

    266:   Level: beginner

    268:   Note:
    269:   This and `VecSetPreallocationCOO() or ``VecSetPreallocationCOOLocal()` provide an alternative API to using `VecSetValues()` to provide vector values.

    271:   This API is particularly efficient for use on GPUs.

    273:   The values must follow the order of the indices prescribed with `VecSetPreallocationCOO()` or `VecSetPreallocationCOOLocal()`.
    274:   When repeated entries are specified in the COO indices the `coo_v` values are first properly summed, regardless of the value of `imode`.
    275:   The imode flag indicates if `coo_v` must be added to the current values of the vector (`ADD_VALUES`) or overwritten (`INSERT_VALUES`).
    276:   `VecAssemblyBegin()` and `VecAssemblyEnd()` do not need to be called after this routine. It automatically handles the assembly process.

    278: .seealso: [](ch_vectors), `Vec`, `VecSetPreallocationCOO()`, `VecSetPreallocationCOOLocal()`, `VecSetValues()`
    279: @*/
    280: PetscErrorCode VecSetValuesCOO(Vec x, const PetscScalar coo_v[], InsertMode imode)
    281: {
    282:   PetscFunctionBegin;
    286:   PetscCall(PetscLogEventBegin(VEC_SetValuesCOO, x, 0, 0, 0));
    287:   if (x->ops->setvaluescoo) {
    288:     PetscUseTypeMethod(x, setvaluescoo, coo_v, imode);
    289:     PetscCall(PetscObjectStateIncrease((PetscObject)x));
    290:   } else {
    291:     IS              is_coo_i;
    292:     const PetscInt *coo_i;
    293:     PetscInt        ncoo;
    294:     PetscMemType    mtype;

    296:     PetscCall(PetscGetMemType(coo_v, &mtype));
    297:     PetscCheck(mtype == PETSC_MEMTYPE_HOST, PetscObjectComm((PetscObject)x), PETSC_ERR_ARG_WRONG, "The basic VecSetValuesCOO() only supports v[] on host");
    298:     PetscCall(PetscObjectQuery((PetscObject)x, "__PETSc_coo_i", (PetscObject *)&is_coo_i));
    299:     PetscCheck(is_coo_i, PetscObjectComm((PetscObject)x), PETSC_ERR_COR, "Missing coo_i IS");
    300:     PetscCall(ISGetLocalSize(is_coo_i, &ncoo));
    301:     PetscCall(ISGetIndices(is_coo_i, &coo_i));
    302:     if (imode != ADD_VALUES) PetscCall(VecZeroEntries(x));
    303:     PetscCall(VecSetValues(x, ncoo, coo_i, coo_v, ADD_VALUES));
    304:     PetscCall(ISRestoreIndices(is_coo_i, &coo_i));
    305:     PetscCall(VecAssemblyBegin(x));
    306:     PetscCall(VecAssemblyEnd(x));
    307:   }
    308:   PetscCall(PetscLogEventEnd(VEC_SetValuesCOO, x, 0, 0, 0));
    309:   PetscFunctionReturn(PETSC_SUCCESS);
    310: }

    312: static PetscErrorCode VecPointwiseApply_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx, PetscLogEvent event, const char async_name[], PetscErrorCode (*const pointwise_op)(Vec, Vec, Vec))
    313: {
    314:   PetscErrorCode (*async_fn)(Vec, Vec, Vec, PetscDeviceContext) = NULL;

    316:   PetscFunctionBegin;
    323:   PetscCheckSameTypeAndComm(x, 2, y, 3);
    324:   PetscCheckSameTypeAndComm(y, 3, w, 1);
    325:   VecCheckSameSize(w, 1, x, 2);
    326:   VecCheckSameSize(w, 1, y, 3);
    327:   VecCheckAssembled(x);
    328:   VecCheckAssembled(y);
    329:   PetscCall(VecSetErrorIfLocked(w, 1));

    332:   if (dctx) PetscCall(PetscObjectQueryFunction((PetscObject)w, async_name, &async_fn));
    333:   if (event) PetscCall(PetscLogEventBegin(event, x, y, w, 0));
    334:   if (async_fn) PetscCall((*async_fn)(w, x, y, dctx));
    335:   else PetscCall((*pointwise_op)(w, x, y));
    336:   if (event) PetscCall(PetscLogEventEnd(event, x, y, w, 0));
    337:   PetscCall(PetscObjectStateIncrease((PetscObject)w));
    338:   PetscFunctionReturn(PETSC_SUCCESS);
    339: }

    341: PetscErrorCode VecPointwiseMaxAsync_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx)
    342: {
    343:   PetscFunctionBegin;
    344:   // REVIEW ME: no log event?
    345:   PetscCall(VecPointwiseApply_Private(w, x, y, dctx, 0, VecAsyncFnName(PointwiseMax), w->ops->pointwisemax));
    346:   PetscFunctionReturn(PETSC_SUCCESS);
    347: }

    349: /*@
    350:   VecPointwiseMax - Computes the component-wise maximum `w[i] = max(x[i], y[i])`.

    352:   Logically Collective

    354:   Input Parameters:
    355: + x - the first input vector
    356: - y - the second input vector

    358:   Output Parameter:
    359: . w - the result

    361:   Level: advanced

    363:   Notes:
    364:   Any subset of the `x`, `y`, and `w` may be the same vector.

    366:   For complex numbers compares only the real part

    368: .seealso: [](ch_vectors), `Vec`, `VecPointwiseDivide()`, `VecPointwiseMult()`, `VecPointwiseMin()`, `VecPointwiseMaxAbs()`, `VecMaxPointwiseDivide()`
    369: @*/
    370: PetscErrorCode VecPointwiseMax(Vec w, Vec x, Vec y)
    371: {
    372:   PetscFunctionBegin;
    373:   PetscCall(VecPointwiseMaxAsync_Private(w, x, y, NULL));
    374:   PetscFunctionReturn(PETSC_SUCCESS);
    375: }

    377: PetscErrorCode VecPointwiseMinAsync_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx)
    378: {
    379:   PetscFunctionBegin;
    380:   // REVIEW ME: no log event?
    381:   PetscCall(VecPointwiseApply_Private(w, x, y, dctx, 0, VecAsyncFnName(PointwiseMin), w->ops->pointwisemin));
    382:   PetscFunctionReturn(PETSC_SUCCESS);
    383: }

    385: /*@
    386:   VecPointwiseMin - Computes the component-wise minimum `w[i] = min(x[i], y[i])`.

    388:   Logically Collective

    390:   Input Parameters:
    391: + x - the first input vector
    392: - y - the second input vector

    394:   Output Parameter:
    395: . w - the result

    397:   Level: advanced

    399:   Notes:
    400:   Any subset of the `x`, `y`, and `w` may be the same vector.

    402:   For complex numbers compares only the real part

    404: .seealso: [](ch_vectors), `Vec`, `VecPointwiseDivide()`, `VecPointwiseMult()`, `VecPointwiseMaxAbs()`, `VecMaxPointwiseDivide()`
    405: @*/
    406: PetscErrorCode VecPointwiseMin(Vec w, Vec x, Vec y)
    407: {
    408:   PetscFunctionBegin;
    409:   PetscCall(VecPointwiseMinAsync_Private(w, x, y, NULL));
    410:   PetscFunctionReturn(PETSC_SUCCESS);
    411: }

    413: PetscErrorCode VecPointwiseMaxAbsAsync_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx)
    414: {
    415:   PetscFunctionBegin;
    416:   // REVIEW ME: no log event?
    417:   PetscCall(VecPointwiseApply_Private(w, x, y, dctx, 0, VecAsyncFnName(PointwiseMaxAbs), w->ops->pointwisemaxabs));
    418:   PetscFunctionReturn(PETSC_SUCCESS);
    419: }

    421: /*@
    422:   VecPointwiseMaxAbs - Computes the component-wise maximum of the absolute values `w[i] = max(abs(x[i]), abs(y[i]))`.

    424:   Logically Collective

    426:   Input Parameters:
    427: + x - the first input vector
    428: - y - the second input vector

    430:   Output Parameter:
    431: . w - the result

    433:   Level: advanced

    435:   Notes:
    436:   Any subset of the `x`, `y`, and `w` may be the same vector.

    438: .seealso: [](ch_vectors), `Vec`, `VecPointwiseDivide()`, `VecPointwiseMult()`, `VecPointwiseMin()`, `VecPointwiseMax()`, `VecMaxPointwiseDivide()`
    439: @*/
    440: PetscErrorCode VecPointwiseMaxAbs(Vec w, Vec x, Vec y)
    441: {
    442:   PetscFunctionBegin;
    443:   PetscCall(VecPointwiseMaxAbsAsync_Private(w, x, y, NULL));
    444:   PetscFunctionReturn(PETSC_SUCCESS);
    445: }

    447: PetscErrorCode VecPointwiseDivideAsync_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx)
    448: {
    449:   PetscFunctionBegin;
    450:   PetscCall(VecPointwiseApply_Private(w, x, y, dctx, VEC_PointwiseDivide, VecAsyncFnName(PointwiseDivide), w->ops->pointwisedivide));
    451:   PetscFunctionReturn(PETSC_SUCCESS);
    452: }

    454: /*@
    455:   VecPointwiseDivide - Computes the component-wise division `w[i] = x[i] / y[i]`.

    457:   Logically Collective

    459:   Input Parameters:
    460: + x - the numerator vector
    461: - y - the denominator vector

    463:   Output Parameter:
    464: . w - the result

    466:   Level: advanced

    468:   Note:
    469:   Any subset of the `x`, `y`, and `w` may be the same vector.

    471: .seealso: [](ch_vectors), `Vec`, `VecPointwiseMult()`, `VecPointwiseMax()`, `VecPointwiseMin()`, `VecPointwiseMaxAbs()`, `VecMaxPointwiseDivide()`
    472: @*/
    473: PetscErrorCode VecPointwiseDivide(Vec w, Vec x, Vec y)
    474: {
    475:   PetscFunctionBegin;
    476:   PetscCall(VecPointwiseDivideAsync_Private(w, x, y, NULL));
    477:   PetscFunctionReturn(PETSC_SUCCESS);
    478: }

    480: #define VEC_POINTWISE_SIGN_LOOP(y, x, n, func) \
    481:   PetscPragmaSIMD \
    482:   for (PetscInt i = 0; i < (n); i++) (y)[i] = func(PetscRealPart((x)[i]))

    484: #define VEC_POINTWISE_SIGN_DISPATCH(y, x, n, sign_type) \
    485:   do { \
    486:     switch (sign_type) { \
    487:     case VEC_SIGN_ZERO_TO_ZERO: \
    488:       VEC_POINTWISE_SIGN_LOOP(y, x, n, VecSignZeroToZero_Private); \
    489:       break; \
    490:     case VEC_SIGN_ZERO_TO_SIGNED_ZERO: \
    491:       VEC_POINTWISE_SIGN_LOOP(y, x, n, VecSignZeroToSignedZero_Private); \
    492:       break; \
    493:     case VEC_SIGN_ZERO_TO_SIGNED_UNIT: \
    494:       VEC_POINTWISE_SIGN_LOOP(y, x, n, VecSignZeroToSignedUnit_Private); \
    495:       break; \
    496:     default: \
    497:       PetscUnreachable(); \
    498:     } \
    499:   } while (0)

    501: PetscErrorCode VecPointwiseSignAsync_Private(Vec y, Vec x, VecSignMode sign_type, PetscDeviceContext dctx)
    502: {
    503:   PetscOffloadMask mask;
    504:   PetscBool        is_host;
    505:   PetscErrorCode (*async_fn)(Vec, Vec, VecSignMode, PetscDeviceContext) = NULL;

    507:   PetscFunctionBegin;
    512:   VecCheckSameSize(y, 1, x, 2);
    513:   VecCheckAssembled(x);
    514:   VecCheckAssembled(y);
    515:   PetscCall(VecSetErrorIfLocked(y, 1));

    517:   PetscCall(VecGetOffloadMask(x, &mask));
    518:   is_host = PetscOffloadHost(mask) ? PETSC_TRUE : PETSC_FALSE;
    519:   if (!is_host) PetscCall(PetscObjectQueryFunction((PetscObject)y, VEC_ASYNC_FN_NAME("PointwiseSign"), &async_fn));
    520:   if (async_fn) PetscCall((*async_fn)(y, x, sign_type, dctx));
    521:   else {
    522:     PetscInt n;

    524:     PetscCall(VecGetLocalSize(y, &n));
    525:     if (y == x) {
    526:       PetscScalar *_y;

    528:       PetscCall(VecGetArray(y, &_y));
    529:       VEC_POINTWISE_SIGN_DISPATCH(_y, _y, n, sign_type);
    530:       PetscCall(VecRestoreArray(y, &_y));
    531:     } else {
    532:       PetscScalar       *_y;
    533:       const PetscScalar *_x;

    535:       PetscCall(VecGetArrayWrite(y, &_y));
    536:       PetscCall(VecGetArrayRead(x, &_x));
    537:       VEC_POINTWISE_SIGN_DISPATCH(_y, _x, n, sign_type);
    538:       PetscCall(VecRestoreArrayRead(x, &_x));
    539:       PetscCall(VecRestoreArrayWrite(y, &_y));
    540:     }
    541:   }
    542:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
    543:   PetscFunctionReturn(PETSC_SUCCESS);
    544: }

    546: /*@
    547:   VecPointwiseSign - Computes the component-wise sign `y[i] = sign(x[i])`.

    549:   Logically Collective

    551:   Input Parameters:
    552: + x         - the input vector
    553: - sign_type - `VecSignMode` indicating how the function should map zero values.

    555:   Output Parameter:
    556: . y - the sign vector of `x`

    558:   Level: beginner

    560: .seealso: [](ch_vectors), `Vec`, `VecSignMode`
    561: @*/
    562: PetscErrorCode VecPointwiseSign(Vec y, Vec x, VecSignMode sign_type)
    563: {
    564:   PetscFunctionBegin;
    565:   PetscCall(VecPointwiseSignAsync_Private(y, x, sign_type, NULL));
    566:   PetscFunctionReturn(PETSC_SUCCESS);
    567: }

    569: PetscErrorCode VecPointwiseMultAsync_Private(Vec w, Vec x, Vec y, PetscDeviceContext dctx)
    570: {
    571:   PetscFunctionBegin;
    573:   PetscCall(VecPointwiseApply_Private(w, x, y, dctx, VEC_PointwiseMult, VecAsyncFnName(PointwiseMult), w->ops->pointwisemult));
    574:   PetscFunctionReturn(PETSC_SUCCESS);
    575: }

    577: /*@
    578:   VecPointwiseMult - Computes the component-wise multiplication `w[i] = x[i] * y[i]`.

    580:   Logically Collective

    582:   Input Parameters:
    583: + x - the first vector
    584: - y - the second vector

    586:   Output Parameter:
    587: . w - the result

    589:   Level: advanced

    591:   Note:
    592:   Any subset of the `x`, `y`, and `w` may be the same vector.

    594: .seealso: [](ch_vectors), `Vec`, `VecPointwiseDivide()`, `VecPointwiseMax()`, `VecPointwiseMin()`, `VecPointwiseMaxAbs()`, `VecMaxPointwiseDivide()`
    595: @*/
    596: PetscErrorCode VecPointwiseMult(Vec w, Vec x, Vec y)
    597: {
    598:   PetscFunctionBegin;
    599:   PetscCall(VecPointwiseMultAsync_Private(w, x, y, NULL));
    600:   PetscFunctionReturn(PETSC_SUCCESS);
    601: }

    603: /*@
    604:   VecDuplicate - Creates a new vector of the same type as an existing vector.

    606:   Collective

    608:   Input Parameter:
    609: . v - a vector to mimic

    611:   Output Parameter:
    612: . newv - location to put new vector

    614:   Level: beginner

    616:   Notes:
    617:   `VecDuplicate()` DOES NOT COPY the vector entries, but rather allocates storage
    618:   for the new vector.  Use `VecCopy()` to copy a vector.

    620:   Use `VecDestroy()` to free the space. Use `VecDuplicateVecs()` to get several
    621:   vectors.

    623: .seealso: [](ch_vectors), `Vec`, `VecDestroy()`, `VecDuplicateVecs()`, `VecCreate()`, `VecCopy()`
    624: @*/
    625: PetscErrorCode VecDuplicate(Vec v, Vec *newv)
    626: {
    627:   PetscFunctionBegin;
    629:   PetscAssertPointer(newv, 2);
    631:   PetscUseTypeMethod(v, duplicate, newv);
    632: #if PetscDefined(HAVE_DEVICE)
    633:   if (v->boundtocpu && v->bindingpropagates) {
    634:     PetscCall(VecSetBindingPropagates(*newv, PETSC_TRUE));
    635:     PetscCall(VecBindToCPU(*newv, PETSC_TRUE));
    636:   }
    637: #endif
    638:   PetscCall(PetscObjectStateIncrease((PetscObject)*newv));
    639:   PetscFunctionReturn(PETSC_SUCCESS);
    640: }

    642: /*@
    643:   VecDestroy - Destroys a vector.

    645:   Collective

    647:   Input Parameter:
    648: . v - the vector

    650:   Level: beginner

    652: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecDuplicate()`, `VecDestroyVecs()`
    653: @*/
    654: PetscErrorCode VecDestroy(Vec *v)
    655: {
    656:   PetscFunctionBegin;
    657:   PetscAssertPointer(v, 1);
    658:   if (!*v) PetscFunctionReturn(PETSC_SUCCESS);
    660:   if (--((PetscObject)*v)->refct > 0) {
    661:     *v = NULL;
    662:     PetscFunctionReturn(PETSC_SUCCESS);
    663:   }

    665:   PetscCall(PetscObjectSAWsViewOff((PetscObject)*v));
    666:   /* destroy the internal part */
    667:   PetscTryTypeMethod(*v, destroy);
    668:   PetscCall(PetscFree((*v)->defaultrandtype));
    669:   /* destroy the external/common part */
    670:   PetscCall(PetscLayoutDestroy(&(*v)->map));
    671:   PetscCall(PetscHeaderDestroy(v));
    672:   PetscFunctionReturn(PETSC_SUCCESS);
    673: }

    675: /*@C
    676:   VecDuplicateVecs - Creates several vectors of the same type as an existing vector.

    678:   Collective

    680:   Input Parameters:
    681: + m - the number of vectors to obtain
    682: - v - a vector to mimic

    684:   Output Parameter:
    685: . V - location to put pointer to array of vectors

    687:   Level: intermediate

    689:   Notes:
    690:   Use `VecDestroyVecs()` to free the space. Use `VecDuplicate()` to form a single
    691:   vector.

    693:   Some implementations ensure that the arrays accessed by each vector are contiguous in memory. Certain `VecMDot()` and `VecMAXPY()`
    694:   implementations utilize this property to use BLAS 2 operations for higher efficiency. This is especially useful in `KSPGMRES`, see
    695:   `KSPGMRESSetPreAllocateVectors()`.

    697:   Fortran Note:
    698: .vb
    699:   Vec, pointer :: V(:)
    700: .ve

    702: .seealso: [](ch_vectors), `Vec`, [](ch_fortran), `VecDestroyVecs()`, `VecDuplicate()`, `VecCreate()`, `VecMDot()`, `VecMAXPY()`, `KSPGMRES`,
    703:           `KSPGMRESSetPreAllocateVectors()`
    704: @*/
    705: PetscErrorCode VecDuplicateVecs(Vec v, PetscInt m, Vec *V[])
    706: {
    707:   PetscFunctionBegin;
    709:   PetscAssertPointer(V, 3);
    711:   PetscUseTypeMethod(v, duplicatevecs, m, V);
    712: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
    713:   if (v->boundtocpu && v->bindingpropagates) {
    714:     PetscInt i;

    716:     for (i = 0; i < m; i++) {
    717:       /* Since ops->duplicatevecs might itself propagate the value of boundtocpu,
    718:        * avoid unnecessary overhead by only calling VecBindToCPU() if the vector isn't already bound. */
    719:       if (!(*V)[i]->boundtocpu) {
    720:         PetscCall(VecSetBindingPropagates((*V)[i], PETSC_TRUE));
    721:         PetscCall(VecBindToCPU((*V)[i], PETSC_TRUE));
    722:       }
    723:     }
    724:   }
    725: #endif
    726:   PetscFunctionReturn(PETSC_SUCCESS);
    727: }

    729: /*@C
    730:   VecDestroyVecs - Frees a block of vectors obtained with `VecDuplicateVecs()`.

    732:   Collective

    734:   Input Parameters:
    735: + m  - the number of vectors previously obtained, if zero no vectors are destroyed
    736: - vv - pointer to pointer to array of vector pointers, if `NULL` no vectors are destroyed

    738:   Level: intermediate

    740: .seealso: [](ch_vectors), `Vec`, [](ch_fortran), `VecDuplicateVecs()`, `VecDestroyVecsf90()`
    741: @*/
    742: PetscErrorCode VecDestroyVecs(PetscInt m, Vec *vv[])
    743: {
    744:   PetscFunctionBegin;
    745:   PetscAssertPointer(vv, 2);
    746:   PetscCheck(m >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Trying to destroy negative number of vectors %" PetscInt_FMT, m);
    747:   if (!m || !*vv) {
    748:     *vv = NULL;
    749:     PetscFunctionReturn(PETSC_SUCCESS);
    750:   }
    753:   PetscCall((*(**vv)->ops->destroyvecs)(m, *vv));
    754:   *vv = NULL;
    755:   PetscFunctionReturn(PETSC_SUCCESS);
    756: }

    758: /*@
    759:   VecViewFromOptions - View a vector based on values in the options database

    761:   Collective

    763:   Input Parameters:
    764: + A    - the vector
    765: . obj  - optional object that provides the options prefix for this viewing, use 'NULL' to use the prefix of `A`
    766: - name - command line option

    768:   Level: intermediate

    770:   Note:
    771:   See `PetscObjectViewFromOptions()` to see the `PetscViewer` and PetscViewerFormat` available

    773: .seealso: [](ch_vectors), `Vec`, `VecView`, `PetscObjectViewFromOptions()`, `VecCreate()`
    774: @*/
    775: PetscErrorCode VecViewFromOptions(Vec A, PeOp PetscObject obj, const char name[])
    776: {
    777:   PetscFunctionBegin;
    779:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
    780:   PetscFunctionReturn(PETSC_SUCCESS);
    781: }

    783: /*@
    784:   VecView - Views a vector object.

    786:   Collective

    788:   Input Parameters:
    789: + vec    - the vector
    790: - viewer - an optional `PetscViewer` visualization context

    792:   Level: beginner

    794:   Notes:
    795:   The available visualization contexts include
    796: +     `PETSC_VIEWER_STDOUT_SELF` - for sequential vectors
    797: .     `PETSC_VIEWER_STDOUT_WORLD` - for parallel vectors created on `PETSC_COMM_WORLD`
    798: -     `PETSC_VIEWER_STDOUT`_(comm) - for parallel vectors created on MPI communicator comm

    800:   You can change the format the vector is printed using the
    801:   option `PetscViewerPushFormat()`.

    803:   The user can open alternative viewers with
    804: +    `PetscViewerASCIIOpen()` - Outputs vector to a specified file
    805: .    `PetscViewerBinaryOpen()` - Outputs vector in binary to a
    806:   specified file; corresponding input uses `VecLoad()`
    807: .    `PetscViewerDrawOpen()` - Outputs vector to an X window display
    808: .    `PetscViewerSocketOpen()` - Outputs vector to Socket viewer
    809: -    `PetscViewerHDF5Open()` - Outputs vector to HDF5 file viewer

    811:   The user can call `PetscViewerPushFormat()` to specify the output
    812:   format of ASCII printed objects (when using `PETSC_VIEWER_STDOUT_SELF`,
    813:   `PETSC_VIEWER_STDOUT_WORLD` and `PetscViewerASCIIOpen()`).  Available formats include
    814: +    `PETSC_VIEWER_DEFAULT` - default, prints vector contents
    815: .    `PETSC_VIEWER_ASCII_MATLAB` - prints vector contents in MATLAB format
    816: .    `PETSC_VIEWER_ASCII_INDEX` - prints vector contents, including indices of vector elements
    817: -    `PETSC_VIEWER_ASCII_COMMON` - prints vector contents, using a
    818:   format common among all vector types

    820:   You can pass any number of vector objects, or other PETSc objects to the same viewer.

    822:   In the debugger you can do call `VecView`(v,0) to display the vector. (The same holds for any PETSc object viewer).

    824:   Notes for binary viewer:
    825:   If you pass multiple vectors to a binary viewer you can read them back in the same order
    826:   with `VecLoad()`.

    828:   If the blocksize of the vector is greater than one then you must provide a unique prefix to
    829:   the vector with `PetscObjectSetOptionsPrefix`((`PetscObject`)vec,"uniqueprefix"); BEFORE calling `VecView()` on the
    830:   vector to be stored and then set that same unique prefix on the vector that you pass to `VecLoad()`. The blocksize
    831:   information is stored in an ASCII file with the same name as the binary file plus a ".info" appended to the
    832:   filename. If you copy the binary file, make sure you copy the associated .info file with it.

    834:   See the manual page for `VecLoad()` on the exact format the binary viewer stores
    835:   the values in the file.

    837:   Notes for HDF5 Viewer:
    838:   The name of the `Vec` (given with `PetscObjectSetName()` is the name that is used
    839:   for the object in the HDF5 file. If you wish to store the same Vec into multiple
    840:   datasets in the same file (typically with different values), you must change its
    841:   name each time before calling the `VecView()`. To load the same vector,
    842:   the name of the Vec object passed to `VecLoad()` must be the same.

    844:   If the block size of the vector is greater than 1 then it is used as the first dimension in the HDF5 array.
    845:   If the function `PetscViewerHDF5SetBaseDimension2()`is called then even if the block size is one it will
    846:   be used as the first dimension in the HDF5 array (that is the HDF5 array will always be two dimensional)
    847:   See also `PetscViewerHDF5SetTimestep()` which adds an additional complication to reading and writing `Vec`
    848:   with the HDF5 viewer.

    850: .seealso: [](ch_vectors), `Vec`, `VecViewFromOptions()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscDrawLGCreate()`,
    851:           `PetscViewerSocketOpen()`, `PetscViewerBinaryOpen()`, `VecLoad()`, `PetscViewerCreate()`,
    852:           `PetscRealView()`, `PetscScalarView()`, `PetscIntView()`, `PetscViewerHDF5SetTimestep()`
    853: @*/
    854: PetscErrorCode VecView(Vec vec, PetscViewer viewer)
    855: {
    856:   PetscBool         isascii;
    857:   PetscViewerFormat format;
    858:   PetscMPIInt       size;

    860:   PetscFunctionBegin;
    863:   VecCheckAssembled(vec);
    864:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)vec), &viewer));
    866:   PetscCall(PetscViewerGetFormat(viewer, &format));
    867:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)vec), &size));
    868:   if (size == 1 && format == PETSC_VIEWER_LOAD_BALANCE) PetscFunctionReturn(PETSC_SUCCESS);

    870:   PetscCheck(!vec->stash.n && !vec->bstash.n, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call VecAssemblyBegin/End() before viewing this vector");

    872:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
    873:   if (isascii) {
    874:     PetscInt rows, bs;

    876:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)vec, viewer));
    877:     if (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
    878:       PetscCall(PetscViewerASCIIPushTab(viewer));
    879:       PetscCall(VecGetSize(vec, &rows));
    880:       PetscCall(VecGetBlockSize(vec, &bs));
    881:       if (bs != 1) {
    882:         PetscCall(PetscViewerASCIIPrintf(viewer, "length=%" PetscInt_FMT ", bs=%" PetscInt_FMT "\n", rows, bs));
    883:       } else {
    884:         PetscCall(PetscViewerASCIIPrintf(viewer, "length=%" PetscInt_FMT "\n", rows));
    885:       }
    886:       PetscCall(PetscViewerASCIIPopTab(viewer));
    887:     }
    888:   }
    889:   PetscCall(VecLockReadPush(vec));
    890:   PetscCall(PetscLogEventBegin(VEC_View, vec, viewer, 0, 0));
    891:   if ((format == PETSC_VIEWER_NATIVE || format == PETSC_VIEWER_LOAD_BALANCE) && vec->ops->viewnative) {
    892:     PetscUseTypeMethod(vec, viewnative, viewer);
    893:   } else {
    894:     PetscUseTypeMethod(vec, view, viewer);
    895:   }
    896:   PetscCall(VecLockReadPop(vec));
    897:   PetscCall(PetscLogEventEnd(VEC_View, vec, viewer, 0, 0));
    898:   PetscFunctionReturn(PETSC_SUCCESS);
    899: }

    901: #if defined(PETSC_USE_DEBUG)
    902: #include <../src/sys/totalview/tv_data_display.h>
    903: PETSC_UNUSED static int TV_display_type(const struct _p_Vec *v)
    904: {
    905:   const PetscScalar *values;
    906:   char               type[32];

    908:   TV_add_row("Local rows", "int", &v->map->n);
    909:   TV_add_row("Global rows", "int", &v->map->N);
    910:   TV_add_row("Typename", TV_ascii_string_type, ((PetscObject)v)->type_name);
    911:   PetscCall(VecGetArrayRead((Vec)v, &values));
    912:   PetscCall(PetscSNPrintf(type, 32, "double[%" PetscInt_FMT "]", v->map->n));
    913:   TV_add_row("values", type, values);
    914:   PetscCall(VecRestoreArrayRead((Vec)v, &values));
    915:   return TV_format_OK;
    916: }
    917: #endif

    919: /*@C
    920:   VecViewNative - Views a vector object with the original type specific viewer

    922:   Collective

    924:   Input Parameters:
    925: + vec    - the vector
    926: - viewer - an optional `PetscViewer` visualization context

    928:   Level: developer

    930:   Note:
    931:   This can be used with, for example, vectors obtained with `DMCreateGlobalVector()` for a `DMDA` to display the vector
    932:   in the PETSc storage format (each MPI process values follow the previous MPI processes) instead of the "natural" grid
    933:   ordering.

    935: .seealso: [](ch_vectors), `Vec`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscDrawLGCreate()`, `VecView()`,
    936:           `PetscViewerSocketOpen()`, `PetscViewerBinaryOpen()`, `VecLoad()`, `PetscViewerCreate()`,
    937:           `PetscRealView()`, `PetscScalarView()`, `PetscIntView()`, `PetscViewerHDF5SetTimestep()`
    938: @*/
    939: PetscErrorCode VecViewNative(Vec vec, PetscViewer viewer)
    940: {
    941:   PetscFunctionBegin;
    944:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)vec), &viewer));
    946:   PetscUseTypeMethod(vec, viewnative, viewer);
    947:   PetscFunctionReturn(PETSC_SUCCESS);
    948: }

    950: /*@
    951:   VecGetSize - Returns the global number of elements of the vector.

    953:   Not Collective

    955:   Input Parameter:
    956: . x - the vector

    958:   Output Parameter:
    959: . size - the global length of the vector

    961:   Level: beginner

    963: .seealso: [](ch_vectors), `Vec`, `VecGetLocalSize()`
    964: @*/
    965: PetscErrorCode VecGetSize(Vec x, PetscInt *size)
    966: {
    967:   PetscFunctionBegin;
    969:   PetscAssertPointer(size, 2);
    971:   PetscUseTypeMethod(x, getsize, size);
    972:   PetscFunctionReturn(PETSC_SUCCESS);
    973: }

    975: /*@
    976:   VecGetLocalSize - Returns the number of elements of the vector stored
    977:   in local memory (that is on this MPI process)

    979:   Not Collective

    981:   Input Parameter:
    982: . x - the vector

    984:   Output Parameter:
    985: . size - the length of the local piece of the vector

    987:   Level: beginner

    989: .seealso: [](ch_vectors), `Vec`, `VecGetSize()`
    990: @*/
    991: PetscErrorCode VecGetLocalSize(Vec x, PetscInt *size)
    992: {
    993:   PetscFunctionBegin;
    995:   PetscAssertPointer(size, 2);
    997:   PetscUseTypeMethod(x, getlocalsize, size);
    998:   PetscFunctionReturn(PETSC_SUCCESS);
    999: }

    1001: /*@
    1002:   VecGetOwnershipRange - Returns the range of indices owned by
    1003:   this process. The vector is laid out with the
    1004:   first `n1` elements on the first processor, next `n2` elements on the
    1005:   second, etc.  For certain parallel layouts this range may not be
    1006:   well defined.

    1008:   Not Collective

    1010:   Input Parameter:
    1011: . x - the vector

    1013:   Output Parameters:
    1014: + low  - the first local element, pass in `NULL` if not interested
    1015: - high - one more than the last local element, pass in `NULL` if not interested

    1017:   Level: beginner

    1019:   Notes:
    1020:   If the `Vec` was obtained from a `DM` with `DMCreateGlobalVector()`, then the range values are determined by the specific `DM`.

    1022:   If the `Vec` was created directly the range values are determined by the local size passed to `VecSetSizes()` or `VecCreateMPI()`.
    1023:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

    1025:   The high argument is one more than the last element stored locally.

    1027:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
    1028:   the local values in the vector.

    1030: .seealso: [](ch_vectors), `Vec`, `MatGetOwnershipRange()`, `MatGetOwnershipRanges()`, `VecGetOwnershipRanges()`, `PetscSplitOwnership()`,
    1031:           `VecSetSizes()`, `VecCreateMPI()`, `PetscLayout`, `DMDAGetGhostCorners()`, `DM`
    1032: @*/
    1033: PetscErrorCode VecGetOwnershipRange(Vec x, PetscInt *low, PetscInt *high)
    1034: {
    1035:   PetscFunctionBegin;
    1038:   if (low) PetscAssertPointer(low, 2);
    1039:   if (high) PetscAssertPointer(high, 3);
    1040:   if (low) *low = x->map->rstart;
    1041:   if (high) *high = x->map->rend;
    1042:   PetscFunctionReturn(PETSC_SUCCESS);
    1043: }

    1045: /*@C
    1046:   VecGetOwnershipRanges - Returns the range of indices owned by EACH processor,
    1047:   The vector is laid out with the
    1048:   first `n1` elements on the first processor, next `n2` elements on the
    1049:   second, etc.  For certain parallel layouts this range may not be
    1050:   well defined.

    1052:   Not Collective

    1054:   Input Parameter:
    1055: . x - the vector

    1057:   Output Parameter:
    1058: . ranges - array of length `size` + 1 with the start and end+1 for each process

    1060:   Level: beginner

    1062:   Notes:
    1063:   If the `Vec` was obtained from a `DM` with `DMCreateGlobalVector()`, then the range values are determined by the specific `DM`.

    1065:   If the `Vec` was created directly the range values are determined by the local size passed to `VecSetSizes()` or `VecCreateMPI()`.
    1066:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

    1068:   The high argument is one more than the last element stored locally.

    1070:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
    1071:   the local values in the vector.

    1073:   The high argument is one more than the last element stored locally.

    1075:   If `ranges` are used after all vectors that share the ranges has been destroyed, then the program will crash accessing `ranges`.

    1077:   Fortran Note:
    1078:   The argument `ranges` must be declared as
    1079: .vb
    1080:   PetscInt, pointer :: ranges(:)
    1081: .ve
    1082:   and you have to return it with a call to `VecRestoreOwnershipRanges()` when no longer needed

    1084: .seealso: [](ch_vectors), `Vec`, `MatGetOwnershipRange()`, `MatGetOwnershipRanges()`, `VecGetOwnershipRange()`, `PetscSplitOwnership()`,
    1085:           `VecSetSizes()`, `VecCreateMPI()`, `PetscLayout`, `DMDAGetGhostCorners()`, `DM`
    1086: @*/
    1087: PetscErrorCode VecGetOwnershipRanges(Vec x, const PetscInt *ranges[])
    1088: {
    1089:   PetscFunctionBegin;
    1092:   PetscCall(PetscLayoutGetRanges(x->map, ranges));
    1093:   PetscFunctionReturn(PETSC_SUCCESS);
    1094: }

    1096: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
    1097: /*@
    1098:   VecSetOption - Sets an option for controlling a vector's behavior.

    1100:   Collective

    1102:   Input Parameters:
    1103: + x    - the vector
    1104: . op   - the option
    1105: - flag - turn the option on or off

    1107:   Supported Options:
    1108: + `VEC_IGNORE_OFF_PROC_ENTRIES` - which causes `VecSetValues()` to ignore
    1109:           entries destined to be stored on a separate processor. This can be used
    1110:           to eliminate the global reduction in the `VecAssemblyBegin()` if you know
    1111:           that you have only used `VecSetValues()` to set local elements
    1112: . `VEC_IGNORE_NEGATIVE_INDICES` - which means you can pass negative indices
    1113:           in ix in calls to `VecSetValues()` or `VecGetValues()`. These rows are simply
    1114:           ignored.
    1115: - `VEC_SUBSET_OFF_PROC_ENTRIES` - which causes `VecAssemblyBegin()` to assume that the off-process
    1116:           entries will always be a subset (possibly equal) of the off-process entries set on the
    1117:           first assembly which had a true `VEC_SUBSET_OFF_PROC_ENTRIES` and the vector has not
    1118:           changed this flag afterwards. If this assembly is not such first assembly, then this
    1119:           assembly can reuse the communication pattern setup in that first assembly, thus avoiding
    1120:           a global reduction. Subsequent assemblies setting off-process values should use the same
    1121:           InsertMode as the first assembly.

    1123:   Level: intermediate

    1125:   Developer Notes:
    1126:   The `InsertMode` restriction could be removed by packing the stash messages out of place.

    1128: .seealso: [](ch_vectors), `Vec`, `VecSetValues()`
    1129: @*/
    1130: PetscErrorCode VecSetOption(Vec x, VecOption op, PetscBool flag)
    1131: {
    1132:   PetscFunctionBegin;
    1135:   PetscTryTypeMethod(x, setoption, op, flag);
    1136:   PetscFunctionReturn(PETSC_SUCCESS);
    1137: }

    1139: /* Default routines for obtaining and releasing; */
    1140: /* may be used by any implementation */
    1141: PetscErrorCode VecDuplicateVecs_Default(Vec w, PetscInt m, Vec *V[])
    1142: {
    1143:   PetscFunctionBegin;
    1144:   PetscCheck(m > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "m must be > 0: m = %" PetscInt_FMT, m);
    1145:   PetscCall(PetscMalloc1(m, V));
    1146:   for (PetscInt i = 0; i < m; i++) PetscCall(VecDuplicate(w, *V + i));
    1147:   PetscFunctionReturn(PETSC_SUCCESS);
    1148: }

    1150: PetscErrorCode VecDestroyVecs_Default(PetscInt m, Vec v[])
    1151: {
    1152:   PetscInt i;

    1154:   PetscFunctionBegin;
    1155:   PetscAssertPointer(v, 2);
    1156:   for (i = 0; i < m; i++) PetscCall(VecDestroy(&v[i]));
    1157:   PetscCall(PetscFree(v));
    1158:   PetscFunctionReturn(PETSC_SUCCESS);
    1159: }

    1161: /*@
    1162:   VecResetArray - Resets a vector to use its default memory. Call this
    1163:   after the use of `VecPlaceArray()`.

    1165:   Not Collective

    1167:   Input Parameter:
    1168: . vec - the vector

    1170:   Level: developer

    1172: .seealso: [](ch_vectors), `Vec`, `VecGetArray()`, `VecRestoreArray()`, `VecReplaceArray()`, `VecPlaceArray()`
    1173: @*/
    1174: PetscErrorCode VecResetArray(Vec vec)
    1175: {
    1176:   PetscFunctionBegin;
    1179:   PetscUseTypeMethod(vec, resetarray);
    1180:   PetscCall(PetscObjectStateIncrease((PetscObject)vec));
    1181:   PetscFunctionReturn(PETSC_SUCCESS);
    1182: }

    1184: /*@
    1185:   VecLoad - Loads a vector that has been stored in binary or HDF5 format
    1186:   with `VecView()`.

    1188:   Collective

    1190:   Input Parameters:
    1191: + vec    - the newly loaded vector, this needs to have been created with `VecCreate()` or
    1192:            some related function before the call to `VecLoad()`.
    1193: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or
    1194:            HDF5 file viewer, obtained from `PetscViewerHDF5Open()`

    1196:   Level: intermediate

    1198:   Notes:
    1199:   Defaults to the standard `VECSEQ` or `VECMPI`, if you want some other type of `Vec` call `VecSetFromOptions()`
    1200:   before calling this.

    1202:   The input file must contain the full global vector, as
    1203:   written by the routine `VecView()`.

    1205:   If the type or size of `vec` is not set before a call to `VecLoad()`, PETSc
    1206:   sets the type and the local and global sizes based on the vector it is reading in. If type and/or
    1207:   sizes are already set, then the same are used.

    1209:   If using the binary viewer and the blocksize of the vector is greater than one then you must provide a unique prefix to
    1210:   the vector with `PetscObjectSetOptionsPrefix`((`PetscObject`)vec,"uniqueprefix"); BEFORE calling `VecView()` on the
    1211:   vector to be stored and then set that same unique prefix on the vector that you pass to VecLoad(). The blocksize
    1212:   information is stored in an ASCII file with the same name as the binary file plus a ".info" appended to the
    1213:   filename. If you copy the binary file, make sure you copy the associated .info file with it.

    1215:   If using HDF5, you must assign the `Vec` the same name as was used in the Vec
    1216:   that was stored in the file using `PetscObjectSetName()`. Otherwise you will
    1217:   get the error message: "Cannot H5DOpen2() with `Vec` name NAMEOFOBJECT".

    1219:   If the HDF5 file contains a two dimensional array the first dimension is treated as the block size
    1220:   in loading the vector. Hence, for example, using MATLAB notation h5create('vector.dat','/Test_Vec',[27 1]);
    1221:   will load a vector of size 27 and block size 27 thus resulting in all 27 entries being on the first process of
    1222:   vectors communicator and the rest of the processes having zero entries

    1224:   Notes for advanced users when using the binary viewer:
    1225:   Most users should not need to know the details of the binary storage
    1226:   format, since `VecLoad()` and `VecView()` completely hide these details.
    1227:   But for anyone who's interested, the standard binary vector storage
    1228:   format is
    1229: .vb
    1230:      PetscInt    VEC_FILE_CLASSID
    1231:      PetscInt    number of rows
    1232:      PetscScalar *values of all entries
    1233: .ve

    1235:   In addition, PETSc automatically uses byte swapping to work on all machines; the files
    1236:   are written ALWAYS using big-endian ordering. On small-endian machines the numbers
    1237:   are converted to the small-endian format when they are read in from the file.
    1238:   See PetscBinaryRead() and PetscBinaryWrite() to see how this may be done.

    1240: .seealso: [](ch_vectors), `Vec`, `PetscViewerBinaryOpen()`, `VecView()`, `MatLoad()`
    1241: @*/
    1242: PetscErrorCode VecLoad(Vec vec, PetscViewer viewer)
    1243: {
    1244:   PetscViewerFormat format;

    1246:   PetscFunctionBegin;
    1249:   PetscCheckSameComm(vec, 1, viewer, 2);

    1251:   PetscCall(VecSetErrorIfLocked(vec, 1));
    1252:   if (!((PetscObject)vec)->type_name && !vec->ops->create) PetscCall(VecSetType(vec, VECSTANDARD));
    1253:   PetscCall(PetscLogEventBegin(VEC_Load, viewer, 0, 0, 0));
    1254:   PetscCall(PetscViewerGetFormat(viewer, &format));
    1255:   if (format == PETSC_VIEWER_NATIVE && vec->ops->loadnative) {
    1256:     PetscUseTypeMethod(vec, loadnative, viewer);
    1257:   } else {
    1258:     PetscUseTypeMethod(vec, load, viewer);
    1259:   }
    1260:   PetscCall(PetscLogEventEnd(VEC_Load, viewer, 0, 0, 0));
    1261:   PetscFunctionReturn(PETSC_SUCCESS);
    1262: }

    1264: /*@
    1265:   VecReciprocal - Replaces each component of a vector by its reciprocal.

    1267:   Logically Collective

    1269:   Input Parameter:
    1270: . vec - the vector

    1272:   Output Parameter:
    1273: . vec - the vector reciprocal

    1275:   Level: intermediate

    1277:   Note:
    1278:   Vector entries with value 0.0 are not changed

    1280: .seealso: [](ch_vectors), `Vec`, `VecLog()`, `VecExp()`, `VecSqrtAbs()`
    1281: @*/
    1282: PetscErrorCode VecReciprocal(Vec vec)
    1283: {
    1284:   PetscFunctionBegin;
    1285:   PetscCall(VecReciprocalAsync_Private(vec, NULL));
    1286:   PetscFunctionReturn(PETSC_SUCCESS);
    1287: }

    1289: /*@C
    1290:   VecSetOperation - Allows the user to override a particular vector operation.

    1292:   Logically Collective; No Fortran Support

    1294:   Input Parameters:
    1295: + vec - The vector to modify
    1296: . op  - The name of the operation
    1297: - f   - The function that provides the operation.

    1299:   Level: advanced

    1301:   Example Usage:
    1302: .vb
    1303:   // some new VecView() implementation, must have the same signature as the function it seeks
    1304:   // to replace
    1305:   PetscErrorCode UserVecView(Vec x, PetscViewer viewer)
    1306:   {
    1307:     PetscFunctionBeginUser;
    1308:     // ...
    1309:     PetscFunctionReturn(PETSC_SUCCESS);
    1310:   }

    1312:   // Create a VECMPI which has a pre-defined VecView() implementation
    1313:   VecCreateMPI(comm, n, N, &x);
    1314:   // Calls the VECMPI implementation for VecView()
    1315:   VecView(x, viewer);

    1317:   VecSetOperation(x, VECOP_VIEW, (PetscErrorCodeFn *)UserVecView);
    1318:   // Now calls UserVecView()
    1319:   VecView(x, viewer);
    1320: .ve

    1322:   Notes:
    1323:   `f` may be `NULL` to remove the operation from `vec`. Depending on the operation this may be
    1324:   allowed, however some always expect a valid function. In these cases an error will be raised
    1325:   when calling the interface routine in question.

    1327:   See `VecOperation` for an up-to-date list of override-able operations. The operations listed
    1328:   there have the form `VECOP_<OPERATION>`, where `<OPERATION>` is the suffix (in all capital
    1329:   letters) of the public interface routine (e.g., `VecView()` -> `VECOP_VIEW`).

    1331:   Overriding a particular `Vec`'s operation has no affect on any other `Vec`s past, present,
    1332:   or future. The user should also note that overriding a method is "destructive"; the previous
    1333:   method is not retained in any way.

    1335:   Each function MUST return `PETSC_SUCCESS` on success and
    1336:   nonzero on failure.

    1338: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecGetOperation()`, `MatSetOperation()`, `MatShellSetOperation()`
    1339: @*/
    1340: PetscErrorCode VecSetOperation(Vec vec, VecOperation op, PetscErrorCodeFn *f)
    1341: {
    1342:   PetscFunctionBegin;
    1344:   if (op == VECOP_VIEW && !vec->ops->viewnative) {
    1345:     vec->ops->viewnative = vec->ops->view;
    1346:   } else if (op == VECOP_LOAD && !vec->ops->loadnative) {
    1347:     vec->ops->loadnative = vec->ops->load;
    1348:   }
    1349:   ((PetscErrorCodeFn **)vec->ops)[(int)op] = f;
    1350:   PetscFunctionReturn(PETSC_SUCCESS);
    1351: }

    1353: /*@
    1354:   VecStashSetInitialSize - sets the sizes of the vec-stash, that is
    1355:   used during the assembly process to store values that belong to
    1356:   other processors.

    1358:   Not Collective, different processes can have different size stashes

    1360:   Input Parameters:
    1361: + vec   - the vector
    1362: . size  - the initial size of the stash.
    1363: - bsize - the initial size of the block-stash(if used).

    1365:   Options Database Keys:
    1366: + -vecstash_initial_size size or size0,size1,...,sizep-1           - set initial size
    1367: - -vecstash_block_initial_size bsize or bsize0,bsize1,...,bsizep-1 - set initial block size

    1369:   Level: intermediate

    1371:   Notes:
    1372:   The block-stash is used for values set with `VecSetValuesBlocked()` while
    1373:   the stash is used for values set with `VecSetValues()`

    1375:   Run with the option -info and look for output of the form
    1376:   VecAssemblyBegin_MPIXXX:Stash has MM entries, uses nn mallocs.
    1377:   to determine the appropriate value, MM, to use for size and
    1378:   VecAssemblyBegin_MPIXXX:Block-Stash has BMM entries, uses nn mallocs.
    1379:   to determine the value, BMM to use for bsize

    1381:   PETSc attempts to smartly manage the stash size so there is little likelihood setting a
    1382:   a specific value here will affect performance

    1384: .seealso: [](ch_vectors), `Vec`, `VecSetBlockSize()`, `VecSetValues()`, `VecSetValuesBlocked()`, `VecStashView()`
    1385: @*/
    1386: PetscErrorCode VecStashSetInitialSize(Vec vec, PetscInt size, PetscInt bsize)
    1387: {
    1388:   PetscFunctionBegin;
    1390:   PetscCall(VecStashSetInitialSize_Private(&vec->stash, size));
    1391:   PetscCall(VecStashSetInitialSize_Private(&vec->bstash, bsize));
    1392:   PetscFunctionReturn(PETSC_SUCCESS);
    1393: }

    1395: /*@
    1396:   VecSetRandom - Sets all components of a vector to random numbers.

    1398:   Logically Collective

    1400:   Input Parameters:
    1401: + x    - the vector
    1402: - rctx - the random number context, formed by `PetscRandomCreate()`, or use `NULL` and it will create one internally.

    1404:   Output Parameter:
    1405: . x - the vector

    1407:   Example of Usage:
    1408: .vb
    1409:      PetscRandomCreate(PETSC_COMM_WORLD,&rctx);
    1410:      VecSetRandom(x,rctx);
    1411:      PetscRandomDestroy(&rctx);
    1412: .ve

    1414:   Level: intermediate

    1416: .seealso: [](ch_vectors), `Vec`, `VecSet()`, `VecSetValues()`, `PetscRandomCreate()`, `PetscRandomDestroy()`
    1417: @*/
    1418: PetscErrorCode VecSetRandom(Vec x, PetscRandom rctx)
    1419: {
    1420:   PetscRandom randObj = NULL;

    1422:   PetscFunctionBegin;
    1426:   VecCheckAssembled(x);
    1427:   PetscCall(VecSetErrorIfLocked(x, 1));

    1429:   if (!rctx) {
    1430:     PetscCall(PetscRandomCreate(PetscObjectComm((PetscObject)x), &randObj));
    1431:     PetscCall(PetscRandomSetType(randObj, x->defaultrandtype));
    1432:     PetscCall(PetscRandomSetFromOptions(randObj));
    1433:     rctx = randObj;
    1434:   }

    1436:   PetscCall(PetscLogEventBegin(VEC_SetRandom, x, rctx, 0, 0));
    1437:   PetscUseTypeMethod(x, setrandom, rctx);
    1438:   PetscCall(PetscLogEventEnd(VEC_SetRandom, x, rctx, 0, 0));

    1440:   PetscCall(PetscRandomDestroy(&randObj));
    1441:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
    1442:   PetscFunctionReturn(PETSC_SUCCESS);
    1443: }

    1445: /*@
    1446:   VecSetRandomGaussian - Fills a vector with Gaussian random values of the given mean and standard deviation.

    1448:   Collective

    1450:   Input Parameters:
    1451: + v       - the vector to fill
    1452: . rng     - PETSc random number generator
    1453: . mean    - desired mean of the Gaussian samples
    1454: - std_dev - desired standard deviation

    1456:   Level: advanced

    1458:   Note:
    1459:   For complex builds where `PetscScalar` is complex the imaginary part of all the vector entries is zero

    1461:   Developer Note:
    1462:   Uses the Box-Muller transform to generate normally distributed random numbers
    1463:   from uniform random numbers. Handles edge cases where uniform random values
    1464:   approach 0 or 1.

    1466: .seealso: [](ch_vectors), [](ch_da), `PetscDA`, `PetscRandom`, `PetscRandomSetInterval()`, `VecSetRandom()`
    1467: @*/
    1468: PetscErrorCode VecSetRandomGaussian(Vec v, PetscRandom rng, PetscReal mean, PetscReal std_dev)
    1469: {
    1470:   PetscInt        n, i;
    1471:   PetscScalar    *array;
    1472:   PetscReal       u1, u2;
    1473:   PetscReal       gauss_sample1, gauss_sample2, magnitude, theta;
    1474:   const PetscReal min_uniform     = PETSC_MACHINE_EPSILON;
    1475:   const PetscInt  max_retry_count = 100;

    1477:   PetscFunctionBegin;
    1482:   PetscCheck(!PetscIsInfOrNanReal(mean), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Mean must be a finite real number");
    1483:   PetscCheck(std_dev >= 0.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Standard deviation must be non-negative, got %g", (double)std_dev);
    1484:   PetscCheck(!PetscIsInfOrNanReal(std_dev), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Standard deviation must be a finite real number");

    1486:   PetscCall(VecGetLocalSize(v, &n));
    1487:   if (n == 0) PetscFunctionReturn(PETSC_SUCCESS);

    1489:   if (std_dev == 0.0) {
    1490:     PetscCall(VecSet(v, mean));
    1491:     PetscFunctionReturn(PETSC_SUCCESS);
    1492:   }

    1494:   PetscCall(VecGetArrayWrite(v, &array));

    1496:   /*
    1497:     Generate Gaussian-distributed random values using the Box-Muller transform.
    1498:     This transform converts pairs of uniform random variables U1, U2 ~ Uniform(0,1)
    1499:     into pairs of independent standard normal variables Z0, Z1 ~ N(0,1):
    1500:       Z0 = sqrt(-2 * ln(U1)) * cos(2pi * U2)
    1501:       Z1 = sqrt(-2 * ln(U1)) * sin(2pi * U2)
    1502:     Then scale and shift to get desired mean and standard deviation.
    1503:   */
    1504:   for (i = 0; i < n; i += 2) {
    1505:     PetscInt retry_count = 0;

    1507:     /*
    1508:       Generate U1 and ensure it's not too close to 0 to avoid log(0) singularity.
    1509:       Add retry limit to prevent infinite loops in case of RNG failure.
    1510:     */
    1511:     do {
    1512:       PetscCall(PetscRandomGetValueReal(rng, &u1));
    1513:       retry_count++;
    1514:       PetscCheck(retry_count < max_retry_count, PETSC_COMM_SELF, PETSC_ERR_LIB, "Random number generator failed to produce valid values after %" PetscInt_FMT " attempts", (PetscInt)max_retry_count);
    1515:     } while (u1 < min_uniform);

    1517:     PetscCall(PetscRandomGetValueReal(rng, &u2));

    1519:     /*
    1520:       Apply Box-Muller transform:
    1521:       - magnitude: sqrt(-2 * ln(U1)) represents the radial distance from origin
    1522:       - theta: 2pi * U2 represents the angle uniformly distributed on [0, 2pi]
    1523:       - Converting from polar to Cartesian coordinates yields two independent samples
    1524:     */
    1525:     magnitude     = PetscSqrtReal(-2.0 * PetscLogReal(u1));
    1526:     theta         = 2.0 * PETSC_PI * u2;
    1527:     gauss_sample1 = magnitude * PetscCosReal(theta);
    1528:     gauss_sample2 = magnitude * PetscSinReal(theta);

    1530:     /* Scale and shift to achieve desired mean and standard deviation */
    1531:     array[i] = mean + std_dev * gauss_sample1;
    1532:     if (i + 1 < n) array[i + 1] = mean + std_dev * gauss_sample2;
    1533:   }

    1535:   PetscCall(VecRestoreArrayWrite(v, &array));
    1536:   PetscFunctionReturn(PETSC_SUCCESS);
    1537: }

    1539: /*@
    1540:   VecZeroEntries - puts a `0.0` in each element of a vector

    1542:   Logically Collective

    1544:   Input Parameter:
    1545: . vec - The vector

    1547:   Level: beginner

    1549:   Note:
    1550:   If the norm of the vector is known to be zero then this skips the unneeded zeroing process

    1552: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecSetOptionsPrefix()`, `VecSet()`, `VecSetValues()`
    1553: @*/
    1554: PetscErrorCode VecZeroEntries(Vec vec)
    1555: {
    1556:   PetscFunctionBegin;
    1557:   PetscCall(VecSet(vec, 0));
    1558:   PetscFunctionReturn(PETSC_SUCCESS);
    1559: }

    1561: /*
    1562:   VecSetTypeFromOptions_Private - Sets the type of vector from user options. Defaults to a PETSc sequential vector on one
    1563:   processor and a PETSc MPI vector on more than one processor.

    1565:   Collective

    1567:   Input Parameter:
    1568: . vec - The vector

    1570:   Level: intermediate

    1572: .seealso: [](ch_vectors), `Vec`, `VecSetFromOptions()`, `VecSetType()`
    1573: */
    1574: static PetscErrorCode VecSetTypeFromOptions_Private(Vec vec, PetscOptionItems PetscOptionsObject)
    1575: {
    1576:   PetscBool   opt;
    1577:   VecType     defaultType;
    1578:   char        typeName[256];
    1579:   PetscMPIInt size;

    1581:   PetscFunctionBegin;
    1582:   if (((PetscObject)vec)->type_name) defaultType = ((PetscObject)vec)->type_name;
    1583:   else {
    1584:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)vec), &size));
    1585:     if (size > 1) defaultType = VECMPI;
    1586:     else defaultType = VECSEQ;
    1587:   }

    1589:   PetscCall(VecRegisterAll());
    1590:   PetscCall(PetscOptionsFList("-vec_type", "Vector type", "VecSetType", VecList, defaultType, typeName, 256, &opt));
    1591:   if (opt) PetscCall(VecSetType(vec, typeName));
    1592:   else PetscCall(VecSetType(vec, defaultType));
    1593:   PetscFunctionReturn(PETSC_SUCCESS);
    1594: }

    1596: /*@
    1597:   VecSetFromOptions - Configures the vector from the options database.

    1599:   Collective

    1601:   Input Parameter:
    1602: . vec - The vector

    1604:   Level: beginner

    1606:   Notes:
    1607:   To see all options, run your program with the -help option.

    1609:   Must be called after `VecCreate()` but before the vector is used.

    1611: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecSetOptionsPrefix()`
    1612: @*/
    1613: PetscErrorCode VecSetFromOptions(Vec vec)
    1614: {
    1615:   PetscBool flg;
    1616:   PetscInt  bind_below = 0;

    1618:   PetscFunctionBegin;

    1621:   PetscObjectOptionsBegin((PetscObject)vec);
    1622:   /* Handle vector type options */
    1623:   PetscCall(VecSetTypeFromOptions_Private(vec, PetscOptionsObject));

    1625:   /* Handle specific vector options */
    1626:   PetscTryTypeMethod(vec, setfromoptions, PetscOptionsObject);

    1628:   /* Bind to CPU if below a user-specified size threshold.
    1629:    * This perhaps belongs in the options for the GPU Vec types, but VecBindToCPU() does nothing when called on non-GPU types,
    1630:    * and putting it here makes is more maintainable than duplicating this for all. */
    1631:   PetscCall(PetscOptionsInt("-vec_bind_below", "Set the size threshold (in local entries) below which the Vec is bound to the CPU", "VecBindToCPU", bind_below, &bind_below, &flg));
    1632:   if (flg && vec->map->n < bind_below) PetscCall(VecBindToCPU(vec, PETSC_TRUE));

    1634:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
    1635:   PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)vec, PetscOptionsObject));
    1636:   PetscOptionsEnd();
    1637:   PetscFunctionReturn(PETSC_SUCCESS);
    1638: }

    1640: /*@
    1641:   VecSetSizes - Sets the local and global sizes, and checks to determine compatibility of the sizes

    1643:   Collective

    1645:   Input Parameters:
    1646: + v - the vector
    1647: . n - the local size (or `PETSC_DECIDE` to have it set)
    1648: - N - the global size (or `PETSC_DETERMINE` to have it set)

    1650:   Level: intermediate

    1652:   Notes:
    1653:   `N` cannot be `PETSC_DETERMINE` if `n` is `PETSC_DECIDE`

    1655:   If one processor calls this with `N` of `PETSC_DETERMINE` then all processors must, otherwise the program will hang.

    1657:   If `n` is not `PETSC_DECIDE`, then the value determines the `PetscLayout` of the vector and the ranges returned by
    1658:   `VecGetOwnershipRange()` and `VecGetOwnershipRanges()`

    1660: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecCreateSeq()`, `VecCreateMPI()`, `VecGetSize()`, `PetscSplitOwnership()`, `PetscLayout`,
    1661:           `VecGetOwnershipRange()`, `VecGetOwnershipRanges()`, `MatSetSizes()`
    1662: @*/
    1663: PetscErrorCode VecSetSizes(Vec v, PetscInt n, PetscInt N)
    1664: {
    1665:   PetscFunctionBegin;
    1667:   if (N >= 0) {
    1669:     PetscCheck(n <= N, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Local size %" PetscInt_FMT " cannot be larger than global size %" PetscInt_FMT, n, N);
    1670:   }
    1671:   PetscCheck(!(v->map->n >= 0 || v->map->N >= 0) || !(v->map->n != n || v->map->N != N), PETSC_COMM_SELF, PETSC_ERR_SUP, "Cannot change/reset vector sizes to %" PetscInt_FMT " local %" PetscInt_FMT " global after previously setting them to %" PetscInt_FMT " local %" PetscInt_FMT " global", n, N,
    1672:              v->map->n, v->map->N);
    1673:   v->map->n = n;
    1674:   v->map->N = N;
    1675:   PetscTryTypeMethod(v, create);
    1676:   v->ops->create = NULL;
    1677:   PetscFunctionReturn(PETSC_SUCCESS);
    1678: }

    1680: /*@
    1681:   VecSetBlockSize - Sets the block size for future calls to `VecSetValuesBlocked()`
    1682:   and `VecSetValuesBlockedLocal()`.

    1684:   Logically Collective

    1686:   Input Parameters:
    1687: + v  - the vector
    1688: - bs - the blocksize

    1690:   Level: advanced

    1692:   Note:
    1693:   All vectors obtained by `VecDuplicate()` inherit the same blocksize.

    1695:   Vectors obtained with `DMCreateGlobalVector()` and `DMCreateLocalVector()` generally already have a blocksize set based on the state of the `DM`

    1697: .seealso: [](ch_vectors), `Vec`, `VecSetValuesBlocked()`, `VecSetLocalToGlobalMapping()`, `VecGetBlockSize()`
    1698: @*/
    1699: PetscErrorCode VecSetBlockSize(Vec v, PetscInt bs)
    1700: {
    1701:   PetscFunctionBegin;
    1704:   PetscCall(PetscLayoutSetBlockSize(v->map, bs));
    1705:   v->bstash.bs = bs; /* use the same blocksize for the vec's block-stash */
    1706:   PetscFunctionReturn(PETSC_SUCCESS);
    1707: }

    1709: /*@
    1710:   VecGetBlockSize - Gets the blocksize for the vector, i.e. what is used for `VecSetValuesBlocked()`
    1711:   and `VecSetValuesBlockedLocal()`.

    1713:   Not Collective

    1715:   Input Parameter:
    1716: . v - the vector

    1718:   Output Parameter:
    1719: . bs - the blocksize

    1721:   Level: advanced

    1723:   Note:
    1724:   All vectors obtained by `VecDuplicate()` inherit the same blocksize.

    1726: .seealso: [](ch_vectors), `Vec`, `VecSetValuesBlocked()`, `VecSetLocalToGlobalMapping()`, `VecSetBlockSize()`
    1727: @*/
    1728: PetscErrorCode VecGetBlockSize(Vec v, PetscInt *bs)
    1729: {
    1730:   PetscFunctionBegin;
    1732:   PetscAssertPointer(bs, 2);
    1733:   PetscCall(PetscLayoutGetBlockSize(v->map, bs));
    1734:   PetscFunctionReturn(PETSC_SUCCESS);
    1735: }

    1737: /*@
    1738:   VecSetOptionsPrefix - Sets the prefix used for searching for all
    1739:   `Vec` options in the database.

    1741:   Logically Collective

    1743:   Input Parameters:
    1744: + v      - the `Vec` context
    1745: - prefix - the prefix to prepend to all option names

    1747:   Level: advanced

    1749:   Note:
    1750:   A hyphen (-) must NOT be given at the beginning of the prefix name.
    1751:   The first character of all runtime options is AUTOMATICALLY the hyphen.

    1753: .seealso: [](ch_vectors), `Vec`, `VecSetFromOptions()`
    1754: @*/
    1755: PetscErrorCode VecSetOptionsPrefix(Vec v, const char prefix[])
    1756: {
    1757:   PetscFunctionBegin;
    1759:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)v, prefix));
    1760:   PetscFunctionReturn(PETSC_SUCCESS);
    1761: }

    1763: /*@
    1764:   VecAppendOptionsPrefix - Appends to the prefix used for searching for all
    1765:   `Vec` options in the database.

    1767:   Logically Collective

    1769:   Input Parameters:
    1770: + v      - the `Vec` context
    1771: - prefix - the prefix to prepend to all option names

    1773:   Level: advanced

    1775:   Note:
    1776:   A hyphen (-) must NOT be given at the beginning of the prefix name.
    1777:   The first character of all runtime options is AUTOMATICALLY the hyphen.

    1779: .seealso: [](ch_vectors), `Vec`, `VecGetOptionsPrefix()`
    1780: @*/
    1781: PetscErrorCode VecAppendOptionsPrefix(Vec v, const char prefix[])
    1782: {
    1783:   PetscFunctionBegin;
    1785:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)v, prefix));
    1786:   PetscFunctionReturn(PETSC_SUCCESS);
    1787: }

    1789: /*@
    1790:   VecGetOptionsPrefix - Sets the prefix used for searching for all
    1791:   Vec options in the database.

    1793:   Not Collective

    1795:   Input Parameter:
    1796: . v - the `Vec` context

    1798:   Output Parameter:
    1799: . prefix - pointer to the prefix string used

    1801:   Level: advanced

    1803: .seealso: [](ch_vectors), `Vec`, `VecAppendOptionsPrefix()`
    1804: @*/
    1805: PetscErrorCode VecGetOptionsPrefix(Vec v, const char *prefix[])
    1806: {
    1807:   PetscFunctionBegin;
    1809:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)v, prefix));
    1810:   PetscFunctionReturn(PETSC_SUCCESS);
    1811: }

    1813: /*@C
    1814:   VecGetState - Gets the state of a `Vec`.

    1816:   Not Collective

    1818:   Input Parameter:
    1819: . v - the `Vec` context

    1821:   Output Parameter:
    1822: . state - the object state

    1824:   Level: advanced

    1826:   Note:
    1827:   Object state is an integer which gets increased every time
    1828:   the object is changed. By saving and later querying the object state
    1829:   one can determine whether information about the object is still current.

    1831: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `PetscObjectStateGet()`
    1832: @*/
    1833: PetscErrorCode VecGetState(Vec v, PetscObjectState *state)
    1834: {
    1835:   PetscFunctionBegin;
    1837:   PetscAssertPointer(state, 2);
    1838:   PetscCall(PetscObjectStateGet((PetscObject)v, state));
    1839:   PetscFunctionReturn(PETSC_SUCCESS);
    1840: }

    1842: /*@
    1843:   VecSetUp - Sets up the internal vector data structures for the later use.

    1845:   Collective

    1847:   Input Parameter:
    1848: . v - the `Vec` context

    1850:   Level: advanced

    1852:   Notes:
    1853:   For basic use of the `Vec` classes the user need not explicitly call
    1854:   `VecSetUp()`, since these actions will happen automatically.

    1856: .seealso: [](ch_vectors), `Vec`, `VecCreate()`, `VecDestroy()`
    1857: @*/
    1858: PetscErrorCode VecSetUp(Vec v)
    1859: {
    1860:   PetscMPIInt size;

    1862:   PetscFunctionBegin;
    1864:   PetscCheck(v->map->n >= 0 || v->map->N >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Sizes not set");
    1865:   if (!((PetscObject)v)->type_name) {
    1866:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)v), &size));
    1867:     if (size == 1) PetscCall(VecSetType(v, VECSEQ));
    1868:     else PetscCall(VecSetType(v, VECMPI));
    1869:   }
    1870:   PetscFunctionReturn(PETSC_SUCCESS);
    1871: }

    1873: /*
    1874:     These currently expose the PetscScalar/PetscReal in updating the
    1875:     cached norm. If we push those down into the implementation these
    1876:     will become independent of PetscScalar/PetscReal
    1877: */

    1879: PetscErrorCode VecCopyAsync_Private(Vec x, Vec y, PetscDeviceContext dctx)
    1880: {
    1881:   PetscBool flgs[4];
    1882:   PetscReal norms[4] = {0.0, 0.0, 0.0, 0.0};

    1884:   PetscFunctionBegin;
    1889:   if (x == y) PetscFunctionReturn(PETSC_SUCCESS);
    1890:   VecCheckSameLocalSize(x, 1, y, 2);
    1891:   VecCheckAssembled(x);
    1892:   PetscCall(VecSetErrorIfLocked(y, 2));

    1894: #if !defined(PETSC_USE_MIXED_PRECISION)
    1895:   for (PetscInt i = 0; i < 4; i++) PetscCall(PetscObjectComposedDataGetReal((PetscObject)x, NormIds[i], norms[i], flgs[i]));
    1896: #endif

    1898:   PetscCall(PetscLogEventBegin(VEC_Copy, x, y, 0, 0));
    1899: #if defined(PETSC_USE_MIXED_PRECISION)
    1900:   extern PetscErrorCode VecGetArray(Vec, double **);
    1901:   extern PetscErrorCode VecRestoreArray(Vec, double **);
    1902:   extern PetscErrorCode VecGetArray(Vec, float **);
    1903:   extern PetscErrorCode VecRestoreArray(Vec, float **);
    1904:   extern PetscErrorCode VecGetArrayRead(Vec, const double **);
    1905:   extern PetscErrorCode VecRestoreArrayRead(Vec, const double **);
    1906:   extern PetscErrorCode VecGetArrayRead(Vec, const float **);
    1907:   extern PetscErrorCode VecRestoreArrayRead(Vec, const float **);
    1908:   if ((((PetscObject)x)->precision == PETSC_PRECISION_SINGLE) && (((PetscObject)y)->precision == PETSC_PRECISION_DOUBLE)) {
    1909:     PetscInt     i, n;
    1910:     const float *xx;
    1911:     double      *yy;
    1912:     PetscCall(VecGetArrayRead(x, &xx));
    1913:     PetscCall(VecGetArray(y, &yy));
    1914:     PetscCall(VecGetLocalSize(x, &n));
    1915:     for (i = 0; i < n; i++) yy[i] = xx[i];
    1916:     PetscCall(VecRestoreArrayRead(x, &xx));
    1917:     PetscCall(VecRestoreArray(y, &yy));
    1918:   } else if ((((PetscObject)x)->precision == PETSC_PRECISION_DOUBLE) && (((PetscObject)y)->precision == PETSC_PRECISION_SINGLE)) {
    1919:     PetscInt      i, n;
    1920:     float        *yy;
    1921:     const double *xx;
    1922:     PetscCall(VecGetArrayRead(x, &xx));
    1923:     PetscCall(VecGetArray(y, &yy));
    1924:     PetscCall(VecGetLocalSize(x, &n));
    1925:     for (i = 0; i < n; i++) yy[i] = (float)xx[i];
    1926:     PetscCall(VecRestoreArrayRead(x, &xx));
    1927:     PetscCall(VecRestoreArray(y, &yy));
    1928:   } else PetscUseTypeMethod(x, copy, y);
    1929: #else
    1930:   VecMethodDispatch(x, dctx, VecAsyncFnName(Copy), copy, (Vec, Vec, PetscDeviceContext), y);
    1931: #endif

    1933:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
    1934: #if !defined(PETSC_USE_MIXED_PRECISION)
    1935:   for (PetscInt i = 0; i < 4; i++) {
    1936:     if (flgs[i]) PetscCall(PetscObjectComposedDataSetReal((PetscObject)y, NormIds[i], norms[i]));
    1937:   }
    1938: #endif

    1940:   PetscCall(PetscLogEventEnd(VEC_Copy, x, y, 0, 0));
    1941:   PetscFunctionReturn(PETSC_SUCCESS);
    1942: }

    1944: /*@
    1945:   VecCopy - Copies a vector `y = x`

    1947:   Logically Collective

    1949:   Input Parameter:
    1950: . x - the vector

    1952:   Output Parameter:
    1953: . y - the copy

    1955:   Level: beginner

    1957:   Note:
    1958:   For default parallel PETSc vectors, both `x` and `y` must be distributed in
    1959:   the same manner; local copies are done.

    1961:   Developer Notes:
    1962:   `PetscCheckSameTypeAndComm`(x,1,y,2) is not used on these vectors because we allow one
    1963:   of the vectors to be sequential and one to be parallel so long as both have the same
    1964:   local sizes. This is used in some internal functions in PETSc.

    1966: .seealso: [](ch_vectors), `Vec`, `VecDuplicate()`
    1967: @*/
    1968: PetscErrorCode VecCopy(Vec x, Vec y)
    1969: {
    1970:   PetscFunctionBegin;
    1971:   PetscCall(VecCopyAsync_Private(x, y, NULL));
    1972:   PetscFunctionReturn(PETSC_SUCCESS);
    1973: }

    1975: PetscErrorCode VecSwapAsync_Private(Vec x, Vec y, PetscDeviceContext dctx)
    1976: {
    1977:   PetscReal normxs[4], normys[4];
    1978:   PetscBool flgxs[4], flgys[4];

    1980:   PetscFunctionBegin;
    1985:   PetscCheckSameTypeAndComm(x, 1, y, 2);
    1986:   VecCheckSameSize(x, 1, y, 2);
    1987:   VecCheckAssembled(x);
    1988:   VecCheckAssembled(y);
    1989:   PetscCall(VecSetErrorIfLocked(x, 1));
    1990:   PetscCall(VecSetErrorIfLocked(y, 2));

    1992:   for (PetscInt i = 0; i < 4; i++) {
    1993:     PetscCall(PetscObjectComposedDataGetReal((PetscObject)x, NormIds[i], normxs[i], flgxs[i]));
    1994:     PetscCall(PetscObjectComposedDataGetReal((PetscObject)y, NormIds[i], normys[i], flgys[i]));
    1995:   }

    1997:   PetscCall(PetscLogEventBegin(VEC_Swap, x, y, 0, 0));
    1998:   VecMethodDispatch(x, dctx, VecAsyncFnName(Swap), swap, (Vec, Vec, PetscDeviceContext), y);
    1999:   PetscCall(PetscLogEventEnd(VEC_Swap, x, y, 0, 0));

    2001:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
    2002:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
    2003:   for (PetscInt i = 0; i < 4; i++) {
    2004:     if (flgxs[i]) PetscCall(PetscObjectComposedDataSetReal((PetscObject)y, NormIds[i], normxs[i]));
    2005:     if (flgys[i]) PetscCall(PetscObjectComposedDataSetReal((PetscObject)x, NormIds[i], normys[i]));
    2006:   }
    2007:   PetscFunctionReturn(PETSC_SUCCESS);
    2008: }
    2009: /*@
    2010:   VecSwap - Swaps the values between two vectors, `x` and `y`.

    2012:   Logically Collective

    2014:   Input Parameters:
    2015: + x - the first vector
    2016: - y - the second vector

    2018:   Level: advanced

    2020: .seealso: [](ch_vectors), `Vec`, `VecSet()`
    2021: @*/
    2022: PetscErrorCode VecSwap(Vec x, Vec y)
    2023: {
    2024:   PetscFunctionBegin;
    2025:   PetscCall(VecSwapAsync_Private(x, y, NULL));
    2026:   PetscFunctionReturn(PETSC_SUCCESS);
    2027: }

    2029: /*@
    2030:   VecStashViewFromOptions - Processes command line options to determine if/how a `VecStash` object is to be viewed.

    2032:   Collective

    2034:   Input Parameters:
    2035: + obj        - the `Vec` containing a stash
    2036: . bobj       - optional other object that provides the prefix
    2037: - optionname - option to activate viewing

    2039:   Level: intermediate

    2041:   Developer Notes:
    2042:   This cannot use `PetscObjectViewFromOptions()` because it takes a `Vec` as an argument but does not use `VecView()`

    2044: .seealso: [](ch_vectors), `Vec`, `VecStashSetInitialSize()`
    2045: @*/
    2046: PetscErrorCode VecStashViewFromOptions(Vec obj, PetscObject bobj, const char optionname[])
    2047: {
    2048:   PetscViewer       viewer;
    2049:   PetscBool         flg;
    2050:   PetscViewerFormat format;
    2051:   char             *prefix;

    2053:   PetscFunctionBegin;
    2054:   prefix = bobj ? bobj->prefix : ((PetscObject)obj)->prefix;
    2055:   PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)obj), ((PetscObject)obj)->options, prefix, optionname, &viewer, &format, &flg));
    2056:   if (flg) {
    2057:     PetscCall(PetscViewerPushFormat(viewer, format));
    2058:     PetscCall(VecStashView(obj, viewer));
    2059:     PetscCall(PetscViewerPopFormat(viewer));
    2060:     PetscCall(PetscViewerDestroy(&viewer));
    2061:   }
    2062:   PetscFunctionReturn(PETSC_SUCCESS);
    2063: }

    2065: /*@
    2066:   VecStashView - Prints the entries in the vector stash and block stash.

    2068:   Collective

    2070:   Input Parameters:
    2071: + v      - the vector
    2072: - viewer - the viewer

    2074:   Level: advanced

    2076: .seealso: [](ch_vectors), `Vec`, `VecSetBlockSize()`, `VecSetValues()`, `VecSetValuesBlocked()`
    2077: @*/
    2078: PetscErrorCode VecStashView(Vec v, PetscViewer viewer)
    2079: {
    2080:   PetscMPIInt rank;
    2081:   PetscInt    i, j;
    2082:   PetscBool   match;
    2083:   VecStash   *s;
    2084:   PetscScalar val;

    2086:   PetscFunctionBegin;
    2089:   PetscCheckSameComm(v, 1, viewer, 2);

    2091:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &match));
    2092:   PetscCheck(match, PETSC_COMM_SELF, PETSC_ERR_SUP, "Stash viewer only works with ASCII viewer not %s", ((PetscObject)v)->type_name);
    2093:   PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_FALSE));
    2094:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)v), &rank));
    2095:   s = &v->bstash;

    2097:   /* print block stash */
    2098:   PetscCall(PetscViewerASCIIPushSynchronized(viewer));
    2099:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "[%d]Vector Block stash size %" PetscInt_FMT " block size %" PetscInt_FMT "\n", rank, s->n, s->bs));
    2100:   for (i = 0; i < s->n; i++) {
    2101:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "[%d] Element %" PetscInt_FMT " ", rank, s->idx[i]));
    2102:     for (j = 0; j < s->bs; j++) {
    2103:       val = s->array[i * s->bs + j];
    2104: #if defined(PETSC_USE_COMPLEX)
    2105:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "(%18.16e %18.16e) ", (double)PetscRealPart(val), (double)PetscImaginaryPart(val)));
    2106: #else
    2107:       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "%18.16e ", (double)val));
    2108: #endif
    2109:     }
    2110:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "\n"));
    2111:   }
    2112:   PetscCall(PetscViewerFlush(viewer));

    2114:   s = &v->stash;

    2116:   /* print basic stash */
    2117:   PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "[%d]Vector stash size %" PetscInt_FMT "\n", rank, s->n));
    2118:   for (i = 0; i < s->n; i++) {
    2119:     val = s->array[i];
    2120: #if defined(PETSC_USE_COMPLEX)
    2121:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "[%d] Element %" PetscInt_FMT " (%18.16e %18.16e) ", rank, s->idx[i], (double)PetscRealPart(val), (double)PetscImaginaryPart(val)));
    2122: #else
    2123:     PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "[%d] Element %" PetscInt_FMT " %18.16e\n", rank, s->idx[i], (double)val));
    2124: #endif
    2125:   }
    2126:   PetscCall(PetscViewerFlush(viewer));
    2127:   PetscCall(PetscViewerASCIIPopSynchronized(viewer));
    2128:   PetscCall(PetscViewerASCIIUseTabs(viewer, PETSC_TRUE));
    2129:   PetscFunctionReturn(PETSC_SUCCESS);
    2130: }

    2132: PetscErrorCode PetscOptionsGetVec(PetscOptions options, const char prefix[], const char key[], Vec v, PetscBool *set)
    2133: {
    2134:   PetscInt     i, N, rstart, rend;
    2135:   PetscScalar *xx;
    2136:   PetscReal   *xreal;
    2137:   PetscBool    iset;

    2139:   PetscFunctionBegin;
    2140:   PetscCall(VecGetOwnershipRange(v, &rstart, &rend));
    2141:   PetscCall(VecGetSize(v, &N));
    2142:   PetscCall(PetscCalloc1(N, &xreal));
    2143:   PetscCall(PetscOptionsGetRealArray(options, prefix, key, xreal, &N, &iset));
    2144:   if (iset) {
    2145:     PetscCall(VecGetArray(v, &xx));
    2146:     for (i = rstart; i < rend; i++) xx[i - rstart] = xreal[i];
    2147:     PetscCall(VecRestoreArray(v, &xx));
    2148:   }
    2149:   PetscCall(PetscFree(xreal));
    2150:   if (set) *set = iset;
    2151:   PetscFunctionReturn(PETSC_SUCCESS);
    2152: }

    2154: /*@
    2155:   VecGetLayout - get `PetscLayout` describing a vector layout

    2157:   Not Collective

    2159:   Input Parameter:
    2160: . x - the vector

    2162:   Output Parameter:
    2163: . map - the layout

    2165:   Level: developer

    2167:   Note:
    2168:   The layout determines what vector elements are contained on each MPI process

    2170: .seealso: [](ch_vectors), `PetscLayout`, `Vec`, `VecGetSize()`, `VecGetOwnershipRange()`, `VecGetOwnershipRanges()`
    2171: @*/
    2172: PetscErrorCode VecGetLayout(Vec x, PetscLayout *map)
    2173: {
    2174:   PetscFunctionBegin;
    2176:   PetscAssertPointer(map, 2);
    2177:   *map = x->map;
    2178:   PetscFunctionReturn(PETSC_SUCCESS);
    2179: }

    2181: /*@
    2182:   VecSetLayout - set `PetscLayout` describing vector layout

    2184:   Not Collective

    2186:   Input Parameters:
    2187: + x   - the vector
    2188: - map - the layout

    2190:   Level: developer

    2192:   Note:
    2193:   It is normally only valid to replace the layout with a layout known to be equivalent.

    2195: .seealso: [](ch_vectors), `Vec`, `PetscLayout`, `VecGetLayout()`, `VecGetSize()`, `VecGetOwnershipRange()`, `VecGetOwnershipRanges()`
    2196: @*/
    2197: PetscErrorCode VecSetLayout(Vec x, PetscLayout map)
    2198: {
    2199:   PetscFunctionBegin;
    2201:   PetscCall(PetscLayoutReference(map, &x->map));
    2202:   PetscFunctionReturn(PETSC_SUCCESS);
    2203: }

    2205: /*@
    2206:   VecFlag - set infinity into the local part of the vector on any subset of MPI processes

    2208:   Logically Collective

    2210:   Input Parameters:
    2211: + xin - the vector, can be `NULL` but only if on all processes
    2212: - flg - indicates if this processes portion of the vector should be set to infinity

    2214:   Level: developer

    2216:   Note:
    2217:   This removes the values from the vector norm cache for all processes by calling `PetscObjectIncrease()`.

    2219:   This is used for any subset of MPI processes to indicate an failure in a solver, after the next use of `VecNorm()` if
    2220:   `KSPCheckNorm()` detects an infinity and at least one of the MPI processes has a not converged reason then the `KSP`
    2221:   object collectively is labeled as not converged.

    2223: .seealso: [](ch_vectors), `Vec`, `PetscLayout`, `VecGetLayout()`, `VecGetSize()`, `VecGetOwnershipRange()`, `VecGetOwnershipRanges()`
    2224: @*/
    2225: PetscErrorCode VecFlag(Vec xin, PetscInt flg)
    2226: {
    2227:   // MSVC gives "divide by zero" error at compile time - so declare as volatile to skip this check.
    2228:   volatile PetscReal one = 1.0, zero = 0.0;
    2229:   PetscScalar        inf;

    2231:   PetscFunctionBegin;
    2232:   if (!xin) PetscFunctionReturn(PETSC_SUCCESS);
    2234:   PetscCall(PetscObjectStateIncrease((PetscObject)xin));
    2235:   if (flg) {
    2236:     PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
    2237:     inf = one / zero;
    2238:     PetscCall(PetscFPTrapPop());
    2239:     if (xin->ops->set) PetscUseTypeMethod(xin, set, inf);
    2240:     else {
    2241:       PetscInt     n;
    2242:       PetscScalar *xx;

    2244:       PetscCall(VecGetLocalSize(xin, &n));
    2245:       PetscCall(VecGetArrayWrite(xin, &xx));
    2246:       for (PetscInt i = 0; i < n; ++i) xx[i] = inf;
    2247:       PetscCall(VecRestoreArrayWrite(xin, &xx));
    2248:     }
    2249:   }
    2250:   PetscFunctionReturn(PETSC_SUCCESS);
    2251: }

    2253: /*@
    2254:   VecSetInf - set infinity into the local part of the vector

    2256:   Not Collective

    2258:   Input Parameters:
    2259: . xin - the vector

    2261:   Level: developer

    2263:   Note:
    2264:   Deprecated, see  `VecFlag()`
    2265:   This is used for any subset of MPI processes to indicate an failure in a solver, after the next use of `VecNorm()` if
    2266:   `KSPCheckNorm()` detects an infinity and at least one of the MPI processes has a not converged reason then the `KSP`
    2267:   object collectively is labeled as not converged.

    2269:   This cannot be called if `xin` has a cached norm available

    2271: .seealso: [](ch_vectors), `VecFlag()`, `Vec`, `PetscLayout`, `VecGetLayout()`, `VecGetSize()`, `VecGetOwnershipRange()`, `VecGetOwnershipRanges()`
    2272: @*/
    2273: PetscErrorCode VecSetInf(Vec xin)
    2274: {
    2275:   // MSVC gives "divide by zero" error at compile time - so declare as volatile to skip this check.
    2276:   volatile PetscReal one = 1.0, zero = 0.0;
    2277:   PetscScalar        inf;
    2278:   PetscBool          flg;

    2280:   PetscFunctionBegin;
    2281:   PetscCall(VecNormAvailable(xin, NORM_2, &flg, NULL));
    2282:   PetscCheck(!flg, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot call VecSetInf() if the vector has a cached norm");
    2283:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
    2284:   inf = one / zero;
    2285:   PetscCall(PetscFPTrapPop());
    2286:   if (xin->ops->set) PetscUseTypeMethod(xin, set, inf);
    2287:   else {
    2288:     PetscInt     n;
    2289:     PetscScalar *xx;

    2291:     PetscCall(VecGetLocalSize(xin, &n));
    2292:     PetscCall(VecGetArrayWrite(xin, &xx));
    2293:     for (PetscInt i = 0; i < n; ++i) xx[i] = inf;
    2294:     PetscCall(VecRestoreArrayWrite(xin, &xx));
    2295:   }
    2296:   PetscFunctionReturn(PETSC_SUCCESS);
    2297: }

    2299: /*@
    2300:   VecBindToCPU - marks a vector to temporarily stay on the CPU and perform computations on the CPU

    2302:   Logically collective

    2304:   Input Parameters:
    2305: + v   - the vector
    2306: - flg - bind to the CPU if value of `PETSC_TRUE`

    2308:   Level: intermediate

    2310: .seealso: [](ch_vectors), `Vec`, `VecBoundToCPU()`
    2311: @*/
    2312: PetscErrorCode VecBindToCPU(Vec v, PetscBool flg)
    2313: {
    2314:   PetscFunctionBegin;
    2317: #if defined(PETSC_HAVE_DEVICE)
    2318:   if (v->boundtocpu == flg) PetscFunctionReturn(PETSC_SUCCESS);
    2319:   v->boundtocpu = flg;
    2320:   PetscTryTypeMethod(v, bindtocpu, flg);
    2321: #endif
    2322:   PetscFunctionReturn(PETSC_SUCCESS);
    2323: }

    2325: /*@
    2326:   VecBoundToCPU - query if a vector is bound to the CPU

    2328:   Not collective

    2330:   Input Parameter:
    2331: . v - the vector

    2333:   Output Parameter:
    2334: . flg - the logical flag

    2336:   Level: intermediate

    2338: .seealso: [](ch_vectors), `Vec`, `VecBindToCPU()`
    2339: @*/
    2340: PetscErrorCode VecBoundToCPU(Vec v, PetscBool *flg)
    2341: {
    2342:   PetscFunctionBegin;
    2344:   PetscAssertPointer(flg, 2);
    2345: #if defined(PETSC_HAVE_DEVICE)
    2346:   *flg = v->boundtocpu;
    2347: #else
    2348:   *flg = PETSC_TRUE;
    2349: #endif
    2350:   PetscFunctionReturn(PETSC_SUCCESS);
    2351: }

    2353: /*@
    2354:   VecSetBindingPropagates - Sets whether the state of being bound to the CPU for a GPU vector type propagates to child and some other associated objects

    2356:   Input Parameters:
    2357: + v   - the vector
    2358: - flg - flag indicating whether the boundtocpu flag should be propagated

    2360:   Level: developer

    2362:   Notes:
    2363:   If the value of flg is set to true, then `VecDuplicate()` and `VecDuplicateVecs()` will bind created vectors to GPU if the input vector is bound to the CPU.
    2364:   The created vectors will also have their bindingpropagates flag set to true.

    2366:   Developer Notes:
    2367:   If a `DMDA` has the `-dm_bind_below option` set to true, then vectors created by `DMCreateGlobalVector()` will have `VecSetBindingPropagates()` called on them to
    2368:   set their bindingpropagates flag to true.

    2370: .seealso: [](ch_vectors), `Vec`, `MatSetBindingPropagates()`, `VecGetBindingPropagates()`
    2371: @*/
    2372: PetscErrorCode VecSetBindingPropagates(Vec v, PetscBool flg)
    2373: {
    2374:   PetscFunctionBegin;
    2376: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
    2377:   v->bindingpropagates = flg;
    2378: #endif
    2379:   PetscFunctionReturn(PETSC_SUCCESS);
    2380: }

    2382: /*@
    2383:   VecGetBindingPropagates - Gets whether the state of being bound to the CPU for a GPU vector type propagates to child and some other associated objects

    2385:   Input Parameter:
    2386: . v - the vector

    2388:   Output Parameter:
    2389: . flg - flag indicating whether the boundtocpu flag will be propagated

    2391:   Level: developer

    2393: .seealso: [](ch_vectors), `Vec`, `VecSetBindingPropagates()`
    2394: @*/
    2395: PetscErrorCode VecGetBindingPropagates(Vec v, PetscBool *flg)
    2396: {
    2397:   PetscFunctionBegin;
    2399:   PetscAssertPointer(flg, 2);
    2400: #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_CUDA) || defined(PETSC_HAVE_HIP)
    2401:   *flg = v->bindingpropagates;
    2402: #else
    2403:   *flg = PETSC_FALSE;
    2404: #endif
    2405:   PetscFunctionReturn(PETSC_SUCCESS);
    2406: }

    2408: /*@C
    2409:   VecSetPinnedMemoryMin - Set the minimum data size for which pinned memory will be used for host (CPU) allocations.

    2411:   Logically Collective

    2413:   Input Parameters:
    2414: + v      - the vector
    2415: - mbytes - minimum data size in bytes

    2417:   Options Database Key:
    2418: . -vec_pinned_memory_min size - minimum size (in bytes) for an allocation to use pinned memory on host.

    2420:   Level: developer

    2422:   Note:
    2423:   Specifying -1 ensures that pinned memory will never be used.

    2425: .seealso: [](ch_vectors), `Vec`, `VecGetPinnedMemoryMin()`
    2426: @*/
    2427: PetscErrorCode VecSetPinnedMemoryMin(Vec v, size_t mbytes)
    2428: {
    2429:   PetscFunctionBegin;
    2431: #if PetscDefined(HAVE_DEVICE)
    2432:   v->minimum_bytes_pinned_memory = mbytes;
    2433: #endif
    2434:   PetscFunctionReturn(PETSC_SUCCESS);
    2435: }

    2437: /*@C
    2438:   VecGetPinnedMemoryMin - Get the minimum data size for which pinned memory will be used for host (CPU) allocations.

    2440:   Logically Collective

    2442:   Input Parameter:
    2443: . v - the vector

    2445:   Output Parameter:
    2446: . mbytes - minimum data size in bytes

    2448:   Level: developer

    2450: .seealso: [](ch_vectors), `Vec`, `VecSetPinnedMemoryMin()`
    2451: @*/
    2452: PetscErrorCode VecGetPinnedMemoryMin(Vec v, size_t *mbytes)
    2453: {
    2454:   PetscFunctionBegin;
    2456:   PetscAssertPointer(mbytes, 2);
    2457: #if PetscDefined(HAVE_DEVICE)
    2458:   *mbytes = v->minimum_bytes_pinned_memory;
    2459: #endif
    2460:   PetscFunctionReturn(PETSC_SUCCESS);
    2461: }

    2463: /*@
    2464:   VecGetOffloadMask - Get the offload mask of a `Vec`

    2466:   Not Collective

    2468:   Input Parameter:
    2469: . v - the vector

    2471:   Output Parameter:
    2472: . mask - corresponding `PetscOffloadMask` enum value.

    2474:   Level: intermediate

    2476: .seealso: [](ch_vectors), `Vec`, `VecCreateSeqCUDA()`, `VecCreateSeqViennaCL()`, `VecGetArray()`, `VecGetType()`
    2477: @*/
    2478: PetscErrorCode VecGetOffloadMask(Vec v, PetscOffloadMask *mask)
    2479: {
    2480:   PetscFunctionBegin;
    2482:   PetscAssertPointer(mask, 2);
    2483:   *mask = v->offloadmask;
    2484:   PetscFunctionReturn(PETSC_SUCCESS);
    2485: }

    2487: #if !defined(PETSC_HAVE_VIENNACL)
    2488: PETSC_EXTERN PetscErrorCode VecViennaCLGetCLContext(Vec v, PETSC_UINTPTR_T *ctx)
    2489: {
    2490:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to get a Vec's cl_context");
    2491: }

    2493: PETSC_EXTERN PetscErrorCode VecViennaCLGetCLQueue(Vec v, PETSC_UINTPTR_T *queue)
    2494: {
    2495:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to get a Vec's cl_command_queue");
    2496: }

    2498: PETSC_EXTERN PetscErrorCode VecViennaCLGetCLMem(Vec v, PETSC_UINTPTR_T *queue)
    2499: {
    2500:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to get a Vec's cl_mem");
    2501: }

    2503: PETSC_EXTERN PetscErrorCode VecViennaCLGetCLMemRead(Vec v, PETSC_UINTPTR_T *queue)
    2504: {
    2505:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to get a Vec's cl_mem");
    2506: }

    2508: PETSC_EXTERN PetscErrorCode VecViennaCLGetCLMemWrite(Vec v, PETSC_UINTPTR_T *queue)
    2509: {
    2510:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to get a Vec's cl_mem");
    2511: }

    2513: PETSC_EXTERN PetscErrorCode VecViennaCLRestoreCLMemWrite(Vec v)
    2514: {
    2515:   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_LIB, "PETSc must be configured with --with-opencl to restore a Vec's cl_mem");
    2516: }
    2517: #endif

    2519: static PetscErrorCode VecErrorWeightedNorms_Basic(Vec U, Vec Y, Vec E, NormType wnormtype, PetscReal atol, Vec vatol, PetscReal rtol, Vec vrtol, PetscReal ignore_max, PetscReal *norm, PetscInt *norm_loc, PetscReal *norma, PetscInt *norma_loc, PetscReal *normr, PetscInt *normr_loc)
    2520: {
    2521:   const PetscScalar *u, *y;
    2522:   const PetscScalar *atola = NULL, *rtola = NULL, *erra = NULL;
    2523:   PetscInt           n, n_loc = 0, na_loc = 0, nr_loc = 0;
    2524:   PetscReal          nrm = 0, nrma = 0, nrmr = 0, err_loc[6];

    2526:   PetscFunctionBegin;
    2527: #define SkipSmallValue(a, b, tol) \
    2528:   if (PetscAbsScalar(a) < tol || PetscAbsScalar(b) < tol) continue

    2530:   PetscCall(VecGetLocalSize(U, &n));
    2531:   PetscCall(VecGetArrayRead(U, &u));
    2532:   PetscCall(VecGetArrayRead(Y, &y));
    2533:   if (E) PetscCall(VecGetArrayRead(E, &erra));
    2534:   if (vatol) PetscCall(VecGetArrayRead(vatol, &atola));
    2535:   if (vrtol) PetscCall(VecGetArrayRead(vrtol, &rtola));
    2536:   for (PetscInt i = 0; i < n; i++) {
    2537:     PetscReal err, tol, tola, tolr;

    2539:     SkipSmallValue(y[i], u[i], ignore_max);
    2540:     atol = atola ? PetscRealPart(atola[i]) : atol;
    2541:     rtol = rtola ? PetscRealPart(rtola[i]) : rtol;
    2542:     err  = erra ? PetscAbsScalar(erra[i]) : PetscAbsScalar(y[i] - u[i]);
    2543:     tola = atol;
    2544:     tolr = rtol * PetscMax(PetscAbsScalar(u[i]), PetscAbsScalar(y[i]));
    2545:     tol  = tola + tolr;
    2546:     if (tola > 0.) {
    2547:       if (wnormtype == NORM_INFINITY) nrma = PetscMax(nrma, err / tola);
    2548:       else nrma += PetscSqr(err / tola);
    2549:       na_loc++;
    2550:     }
    2551:     if (tolr > 0.) {
    2552:       if (wnormtype == NORM_INFINITY) nrmr = PetscMax(nrmr, err / tolr);
    2553:       else nrmr += PetscSqr(err / tolr);
    2554:       nr_loc++;
    2555:     }
    2556:     if (tol > 0.) {
    2557:       if (wnormtype == NORM_INFINITY) nrm = PetscMax(nrm, err / tol);
    2558:       else nrm += PetscSqr(err / tol);
    2559:       n_loc++;
    2560:     }
    2561:   }
    2562:   if (E) PetscCall(VecRestoreArrayRead(E, &erra));
    2563:   if (vatol) PetscCall(VecRestoreArrayRead(vatol, &atola));
    2564:   if (vrtol) PetscCall(VecRestoreArrayRead(vrtol, &rtola));
    2565:   PetscCall(VecRestoreArrayRead(U, &u));
    2566:   PetscCall(VecRestoreArrayRead(Y, &y));
    2567: #undef SkipSmallValue

    2569:   err_loc[0] = nrm;
    2570:   err_loc[1] = nrma;
    2571:   err_loc[2] = nrmr;
    2572:   err_loc[3] = (PetscReal)n_loc;
    2573:   err_loc[4] = (PetscReal)na_loc;
    2574:   err_loc[5] = (PetscReal)nr_loc;
    2575:   if (wnormtype == NORM_2) {
    2576:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, err_loc, 6, MPIU_REAL, MPIU_SUM, PetscObjectComm((PetscObject)U)));
    2577:   } else {
    2578:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, err_loc, 3, MPIU_REAL, MPIU_MAX, PetscObjectComm((PetscObject)U)));
    2579:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, err_loc + 3, 3, MPIU_REAL, MPIU_SUM, PetscObjectComm((PetscObject)U)));
    2580:   }
    2581:   if (wnormtype == NORM_2) {
    2582:     *norm  = PetscSqrtReal(err_loc[0]);
    2583:     *norma = PetscSqrtReal(err_loc[1]);
    2584:     *normr = PetscSqrtReal(err_loc[2]);
    2585:   } else {
    2586:     *norm  = err_loc[0];
    2587:     *norma = err_loc[1];
    2588:     *normr = err_loc[2];
    2589:   }
    2590:   *norm_loc  = (PetscInt)err_loc[3];
    2591:   *norma_loc = (PetscInt)err_loc[4];
    2592:   *normr_loc = (PetscInt)err_loc[5];
    2593:   PetscFunctionReturn(PETSC_SUCCESS);
    2594: }

    2596: /*@
    2597:   VecErrorWeightedNorms - compute a weighted norm of the difference between two vectors

    2599:   Collective

    2601:   Input Parameters:
    2602: + U          - first vector to be compared
    2603: . Y          - second vector to be compared
    2604: . E          - optional third vector representing the error (if not provided, the error is ||U-Y||)
    2605: . wnormtype  - norm type
    2606: . atol       - scalar for absolute tolerance
    2607: . vatol      - vector representing per-entry absolute tolerances (can be ``NULL``)
    2608: . rtol       - scalar for relative tolerance
    2609: . vrtol      - vector representing per-entry relative tolerances (can be ``NULL``)
    2610: - ignore_max - ignore values smaller than this value in absolute terms.

    2612:   Output Parameters:
    2613: + norm      - weighted norm
    2614: . norm_loc  - number of vector locations used for the weighted norm
    2615: . norma     - weighted norm based on the absolute tolerance
    2616: . norma_loc - number of vector locations used for the absolute weighted norm
    2617: . normr     - weighted norm based on the relative tolerance
    2618: - normr_loc - number of vector locations used for the relative weighted norm

    2620:   Level: developer

    2622:   Notes:
    2623:   This is primarily used for computing weighted local truncation errors in ``TS``.

    2625: .seealso: [](ch_vectors), `Vec`, `NormType`, `TSErrorWeightedNorm()`, `TSErrorWeightedENorm()`
    2626: @*/
    2627: PetscErrorCode VecErrorWeightedNorms(Vec U, Vec Y, Vec E, NormType wnormtype, PetscReal atol, Vec vatol, PetscReal rtol, Vec vrtol, PetscReal ignore_max, PetscReal *norm, PetscInt *norm_loc, PetscReal *norma, PetscInt *norma_loc, PetscReal *normr, PetscInt *normr_loc)
    2628: {
    2629:   PetscFunctionBegin;
    2634:   if (E) {
    2637:   }
    2640:   if (vatol) {
    2643:   }
    2645:   if (vrtol) {
    2648:   }
    2650:   PetscAssertPointer(norm, 10);
    2651:   PetscAssertPointer(norm_loc, 11);
    2652:   PetscAssertPointer(norma, 12);
    2653:   PetscAssertPointer(norma_loc, 13);
    2654:   PetscAssertPointer(normr, 14);
    2655:   PetscAssertPointer(normr_loc, 15);
    2656:   PetscCheck(wnormtype == NORM_2 || wnormtype == NORM_INFINITY, PetscObjectComm((PetscObject)U), PETSC_ERR_SUP, "No support for norm type %s", NormTypes[wnormtype]);

    2658:   /* There are potentially 5 vectors involved, some of them may happen to be of different type or bound to cpu.
    2659:      Here we check that they all implement the same operation and call it if so.
    2660:      Otherwise, we call the _Basic implementation that always works (provided VecGetArrayRead is implemented). */
    2661:   PetscBool sameop = (PetscBool)(U->ops->errorwnorm && U->ops->errorwnorm == Y->ops->errorwnorm);
    2662:   if (sameop && E) sameop = (PetscBool)(U->ops->errorwnorm == E->ops->errorwnorm);
    2663:   if (sameop && vatol) sameop = (PetscBool)(U->ops->errorwnorm == vatol->ops->errorwnorm);
    2664:   if (sameop && vrtol) sameop = (PetscBool)(U->ops->errorwnorm == vrtol->ops->errorwnorm);
    2665:   if (sameop) PetscUseTypeMethod(U, errorwnorm, Y, E, wnormtype, atol, vatol, rtol, vrtol, ignore_max, norm, norm_loc, norma, norma_loc, normr, normr_loc);
    2666:   else PetscCall(VecErrorWeightedNorms_Basic(U, Y, E, wnormtype, atol, vatol, rtol, vrtol, ignore_max, norm, norm_loc, norma, norma_loc, normr, normr_loc));
    2667:   PetscFunctionReturn(PETSC_SUCCESS);
    2668: }