Date: 2022-03-31T04:48:06+00:00

Actual source code: itcreate.c

      1: /*
      2:      The basic KSP routines, Create, View etc. are here.
      3: */
      4: #include <petsc/private/kspimpl.h>

      6: /* Logging support */
      7: PetscClassId  KSP_CLASSID;
      8: PetscClassId  DMKSP_CLASSID;
      9: PetscClassId  KSPGUESS_CLASSID;
     10: PetscLogEvent KSP_GMRESOrthogonalization, KSP_SetUp, KSP_Solve, KSP_SolveTranspose, KSP_MatSolve;

     12: /*
     13:    Contains the list of registered KSP routines
     14: */
     15: PetscFunctionList KSPList              = NULL;
     16: PetscBool         KSPRegisterAllCalled = PETSC_FALSE;

     18: /*
     19:    Contains the list of registered KSP monitors
     20: */
     21: PetscFunctionList KSPMonitorList              = NULL;
     22: PetscFunctionList KSPMonitorCreateList        = NULL;
     23: PetscFunctionList KSPMonitorDestroyList       = NULL;
     24: PetscBool         KSPMonitorRegisterAllCalled = PETSC_FALSE;

     26: /*@C
     27:   KSPLoad - Loads a KSP that has been stored in binary  with KSPView().

     29:   Collective on viewer

     31:   Input Parameters:
     32: + newdm - the newly loaded KSP, this needs to have been created with KSPCreate() or
     33:            some related function before a call to KSPLoad().
     34: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()

     36:    Level: intermediate

     38:   Notes:
     39:    The type is determined by the data in the file, any type set into the KSP before this call is ignored.

     41:   Notes for advanced users:
     42:   Most users should not need to know the details of the binary storage
     43:   format, since KSPLoad() and KSPView() completely hide these details.
     44:   But for anyone who's interested, the standard binary matrix storage
     45:   format is
     46: .vb
     47:      has not yet been determined
     48: .ve

     50: .seealso: PetscViewerBinaryOpen(), KSPView(), MatLoad(), VecLoad()
     51: @*/
     52: PetscErrorCode  KSPLoad(KSP newdm, PetscViewer viewer)
     53: {
     54:   PetscBool      isbinary;
     55:   PetscInt       classid;
     56:   char           type[256];
     57:   PC             pc;

     61:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);

     64:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
     66:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
     67:   KSPSetType(newdm, type);
     68:   if (newdm->ops->load) (*newdm->ops->load)(newdm,viewer);
     69:   KSPGetPC(newdm,&pc);
     70:   PCLoad(pc,viewer);
     71:   return 0;
     72: }

     74: #include <petscdraw.h>
     75: #if defined(PETSC_HAVE_SAWS)
     76: #include <petscviewersaws.h>
     77: #endif
     78: /*@C
     79:    KSPView - Prints the KSP data structure.

     81:    Collective on ksp

     83:    Input Parameters:
     84: +  ksp - the Krylov space context
     85: -  viewer - visualization context

     87:    Options Database Keys:
     88: .  -ksp_view - print the KSP data structure at the end of a KSPSolve call

     90:    Note:
     91:    The available visualization contexts include
     92: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
     93: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
     94:          output where only the first processor opens
     95:          the file.  All other processors send their
     96:          data to the first processor to print.

     98:    The available formats include
     99: +     PETSC_VIEWER_DEFAULT - standard output (default)
    100: -     PETSC_VIEWER_ASCII_INFO_DETAIL - more verbose output for PCBJACOBI and PCASM

    102:    The user can open an alternative visualization context with
    103:    PetscViewerASCIIOpen() - output to a specified file.

    105:   In the debugger you can do "call KSPView(ksp,0)" to display the KSP. (The same holds for any PETSc object viewer).

    107:    Level: beginner

    109: .seealso: PCView(), PetscViewerASCIIOpen()
    110: @*/
    111: PetscErrorCode  KSPView(KSP ksp,PetscViewer viewer)
    112: {
    113:   PetscBool      iascii,isbinary,isdraw,isstring;
    114: #if defined(PETSC_HAVE_SAWS)
    115:   PetscBool      issaws;
    116: #endif

    119:   if (!viewer) {
    120:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ksp),&viewer);
    121:   }

    125:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
    126:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
    127:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
    128:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
    129: #if defined(PETSC_HAVE_SAWS)
    130:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
    131: #endif
    132:   if (iascii) {
    133:     PetscObjectPrintClassNamePrefixType((PetscObject)ksp,viewer);
    134:     if (ksp->ops->view) {
    135:       PetscViewerASCIIPushTab(viewer);
    136:       (*ksp->ops->view)(ksp,viewer);
    137:       PetscViewerASCIIPopTab(viewer);
    138:     }
    139:     if (ksp->guess_zero) {
    140:       PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, initial guess is zero\n",ksp->max_it);
    141:     } else {
    142:       PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, nonzero initial guess\n", ksp->max_it);
    143:     }
    144:     if (ksp->guess_knoll) PetscViewerASCIIPrintf(viewer,"  using preconditioner applied to right hand side for initial guess\n");
    145:     PetscViewerASCIIPrintf(viewer,"  tolerances:  relative=%g, absolute=%g, divergence=%g\n",(double)ksp->rtol,(double)ksp->abstol,(double)ksp->divtol);
    146:     if (ksp->pc_side == PC_RIGHT) {
    147:       PetscViewerASCIIPrintf(viewer,"  right preconditioning\n");
    148:     } else if (ksp->pc_side == PC_SYMMETRIC) {
    149:       PetscViewerASCIIPrintf(viewer,"  symmetric preconditioning\n");
    150:     } else {
    151:       PetscViewerASCIIPrintf(viewer,"  left preconditioning\n");
    152:     }
    153:     if (ksp->guess) {
    154:       PetscViewerASCIIPushTab(viewer);
    155:       KSPGuessView(ksp->guess,viewer);
    156:       PetscViewerASCIIPopTab(viewer);
    157:     }
    158:     if (ksp->dscale) PetscViewerASCIIPrintf(viewer,"  diagonally scaled system\n");
    159:     PetscViewerASCIIPrintf(viewer,"  using %s norm type for convergence test\n",KSPNormTypes[ksp->normtype]);
    160:   } else if (isbinary) {
    161:     PetscInt    classid = KSP_FILE_CLASSID;
    162:     MPI_Comm    comm;
    163:     PetscMPIInt rank;
    164:     char        type[256];

    166:     PetscObjectGetComm((PetscObject)ksp,&comm);
    167:     MPI_Comm_rank(comm,&rank);
    168:     if (rank == 0) {
    169:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT);
    170:       PetscStrncpy(type,((PetscObject)ksp)->type_name,256);
    171:       PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR);
    172:     }
    173:     if (ksp->ops->view) {
    174:       (*ksp->ops->view)(ksp,viewer);
    175:     }
    176:   } else if (isstring) {
    177:     const char *type;
    178:     KSPGetType(ksp,&type);
    179:     PetscViewerStringSPrintf(viewer," KSPType: %-7.7s",type);
    180:     if (ksp->ops->view) (*ksp->ops->view)(ksp,viewer);
    181:   } else if (isdraw) {
    182:     PetscDraw draw;
    183:     char      str[36];
    184:     PetscReal x,y,bottom,h;
    185:     PetscBool flg;

    187:     PetscViewerDrawGetDraw(viewer,0,&draw);
    188:     PetscDrawGetCurrentPoint(draw,&x,&y);
    189:     PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
    190:     if (!flg) {
    191:       PetscStrncpy(str,"KSP: ",sizeof(str));
    192:       PetscStrlcat(str,((PetscObject)ksp)->type_name,sizeof(str));
    193:       PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
    194:       bottom = y - h;
    195:     } else {
    196:       bottom = y;
    197:     }
    198:     PetscDrawPushCurrentPoint(draw,x,bottom);
    199: #if defined(PETSC_HAVE_SAWS)
    200:   } else if (issaws) {
    201:     PetscMPIInt rank;
    202:     const char  *name;

    204:     PetscObjectGetName((PetscObject)ksp,&name);
    205:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
    206:     if (!((PetscObject)ksp)->amsmem && rank == 0) {
    207:       char       dir[1024];

    209:       PetscObjectViewSAWs((PetscObject)ksp,viewer);
    210:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
    211:       PetscStackCallSAWs(SAWs_Register,(dir,&ksp->its,1,SAWs_READ,SAWs_INT));
    212:       if (!ksp->res_hist) {
    213:         KSPSetResidualHistory(ksp,NULL,PETSC_DECIDE,PETSC_TRUE);
    214:       }
    215:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/res_hist",name);
    216:       PetscStackCallSAWs(SAWs_Register,(dir,ksp->res_hist,10,SAWs_READ,SAWs_DOUBLE));
    217:     }
    218: #endif
    219:   } else if (ksp->ops->view) {
    220:     (*ksp->ops->view)(ksp,viewer);
    221:   }
    222:   if (ksp->pc) {
    223:     PCView(ksp->pc,viewer);
    224:   }
    225:   if (isdraw) {
    226:     PetscDraw draw;
    227:     PetscViewerDrawGetDraw(viewer,0,&draw);
    228:     PetscDrawPopCurrentPoint(draw);
    229:   }
    230:   return 0;
    231: }

    233: /*@C
    234:    KSPViewFromOptions - View from Options

    236:    Collective on KSP

    238:    Input Parameters:
    239: +  A - Krylov solver context
    240: .  obj - Optional object
    241: -  name - command line option

    243:    Level: intermediate
    244: .seealso:  KSP, KSPView, PetscObjectViewFromOptions(), KSPCreate()
    245: @*/
    246: PetscErrorCode  KSPViewFromOptions(KSP A,PetscObject obj,const char name[])
    247: {
    249:   PetscObjectViewFromOptions((PetscObject)A,obj,name);
    250:   return 0;
    251: }

    253: /*@
    254:    KSPSetNormType - Sets the norm that is used for convergence testing.

    256:    Logically Collective on ksp

    258:    Input Parameters:
    259: +  ksp - Krylov solver context
    260: -  normtype - one of
    261: $   KSP_NORM_NONE - skips computing the norm, this should generally only be used if you are using
    262: $                 the Krylov method as a smoother with a fixed small number of iterations.
    263: $                 Implicitly sets KSPConvergedSkip() as KSP convergence test.
    264: $                 Note that certain algorithms such as KSPGMRES ALWAYS require the norm calculation,
    265: $                 for these methods the norms are still computed, they are just not used in
    266: $                 the convergence test.
    267: $   KSP_NORM_PRECONDITIONED - the default for left preconditioned solves, uses the l2 norm
    268: $                 of the preconditioned residual P^{-1}(b - A x)
    269: $   KSP_NORM_UNPRECONDITIONED - uses the l2 norm of the true b - Ax residual.
    270: $   KSP_NORM_NATURAL - supported  by KSPCG, KSPCR, KSPCGNE, KSPCGS

    272:    Options Database Key:
    273: .   -ksp_norm_type <none,preconditioned,unpreconditioned,natural> - set KSP norm type

    275:    Notes:
    276:    Not all combinations of preconditioner side (see KSPSetPCSide()) and norm type are supported by all Krylov methods.
    277:    If only one is set, PETSc tries to automatically change the other to find a compatible pair.  If no such combination
    278:    is supported, PETSc will generate an error.

    280:    Developer Notes:
    281:    Supported combinations of norm and preconditioner side are set using KSPSetSupportedNorm().

    283:    Level: advanced

    285: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetCheckNormIteration(), KSPSetPCSide(), KSPGetPCSide(), KSPNormType
    286: @*/
    287: PetscErrorCode  KSPSetNormType(KSP ksp,KSPNormType normtype)
    288: {
    291:   ksp->normtype = ksp->normtype_set = normtype;
    292:   return 0;
    293: }

    295: /*@
    296:    KSPSetCheckNormIteration - Sets the first iteration at which the norm of the residual will be
    297:      computed and used in the convergence test.

    299:    Logically Collective on ksp

    301:    Input Parameters:
    302: +  ksp - Krylov solver context
    303: -  it  - use -1 to check at all iterations

    305:    Notes:
    306:    Currently only works with KSPCG, KSPBCGS and KSPIBCGS

    308:    Use KSPSetNormType(ksp,KSP_NORM_NONE) to never check the norm

    310:    On steps where the norm is not computed, the previous norm is still in the variable, so if you run with, for example,
    311:     -ksp_monitor the residual norm will appear to be unchanged for several iterations (though it is not really unchanged).
    312:    Level: advanced

    314: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType()
    315: @*/
    316: PetscErrorCode  KSPSetCheckNormIteration(KSP ksp,PetscInt it)
    317: {
    320:   ksp->chknorm = it;
    321:   return 0;
    322: }

    324: /*@
    325:    KSPSetLagNorm - Lags the residual norm calculation so that it is computed as part of the MPI_Allreduce() for
    326:    computing the inner products for the next iteration.  This can reduce communication costs at the expense of doing
    327:    one additional iteration.

    329:    Logically Collective on ksp

    331:    Input Parameters:
    332: +  ksp - Krylov solver context
    333: -  flg - PETSC_TRUE or PETSC_FALSE

    335:    Options Database Keys:
    336: .  -ksp_lag_norm - lag the calculated residual norm

    338:    Notes:
    339:    Currently only works with KSPIBCGS.

    341:    Use KSPSetNormType(ksp,KSP_NORM_NONE) to never check the norm

    343:    If you lag the norm and run with, for example, -ksp_monitor, the residual norm reported will be the lagged one.
    344:    Level: advanced

    346: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType(), KSPSetCheckNormIteration()
    347: @*/
    348: PetscErrorCode  KSPSetLagNorm(KSP ksp,PetscBool flg)
    349: {
    352:   ksp->lagnorm = flg;
    353:   return 0;
    354: }

    356: /*@
    357:    KSPSetSupportedNorm - Sets a norm and preconditioner side supported by a KSP

    359:    Logically Collective

    361:    Input Parameters:
    362: +  ksp - Krylov method
    363: .  normtype - supported norm type
    364: .  pcside - preconditioner side that can be used with this norm
    365: -  priority - positive integer preference for this combination; larger values have higher priority

    367:    Level: developer

    369:    Notes:
    370:    This function should be called from the implementation files KSPCreate_XXX() to declare
    371:    which norms and preconditioner sides are supported. Users should not need to call this
    372:    function.

    374: .seealso: KSPSetNormType(), KSPSetPCSide()
    375: @*/
    376: PetscErrorCode KSPSetSupportedNorm(KSP ksp,KSPNormType normtype,PCSide pcside,PetscInt priority)
    377: {
    379:   ksp->normsupporttable[normtype][pcside] = priority;
    380:   return 0;
    381: }

    383: PetscErrorCode KSPNormSupportTableReset_Private(KSP ksp)
    384: {
    385:   PetscMemzero(ksp->normsupporttable,sizeof(ksp->normsupporttable));
    386:   ksp->pc_side  = ksp->pc_side_set;
    387:   ksp->normtype = ksp->normtype_set;
    388:   return 0;
    389: }

    391: PetscErrorCode KSPSetUpNorms_Private(KSP ksp,PetscBool errorifnotsupported,KSPNormType *normtype,PCSide *pcside)
    392: {
    393:   PetscInt i,j,best,ibest = 0,jbest = 0;

    395:   best = 0;
    396:   for (i=0; i<KSP_NORM_MAX; i++) {
    397:     for (j=0; j<PC_SIDE_MAX; j++) {
    398:       if ((ksp->normtype == KSP_NORM_DEFAULT || ksp->normtype == i) && (ksp->pc_side == PC_SIDE_DEFAULT || ksp->pc_side == j) && (ksp->normsupporttable[i][j] > best)) {
    399:         best  = ksp->normsupporttable[i][j];
    400:         ibest = i;
    401:         jbest = j;
    402:       }
    403:     }
    404:   }
    405:   if (best < 1 && errorifnotsupported) {
    409:     SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"KSP %s does not support %s with %s",((PetscObject)ksp)->type_name,KSPNormTypes[ksp->normtype],PCSides[ksp->pc_side]);
    410:   }
    411:   if (normtype) *normtype = (KSPNormType)ibest;
    412:   if (pcside)   *pcside   = (PCSide)jbest;
    413:   return 0;
    414: }

    416: /*@
    417:    KSPGetNormType - Gets the norm that is used for convergence testing.

    419:    Not Collective

    421:    Input Parameter:
    422: .  ksp - Krylov solver context

    424:    Output Parameter:
    425: .  normtype - norm that is used for convergence testing

    427:    Level: advanced

    429: .seealso: KSPNormType, KSPSetNormType(), KSPConvergedSkip()
    430: @*/
    431: PetscErrorCode  KSPGetNormType(KSP ksp, KSPNormType *normtype)
    432: {
    435:   KSPSetUpNorms_Private(ksp,PETSC_TRUE,&ksp->normtype,&ksp->pc_side);
    436:   *normtype = ksp->normtype;
    437:   return 0;
    438: }

    440: #if defined(PETSC_HAVE_SAWS)
    441: #include <petscviewersaws.h>
    442: #endif

    444: /*@
    445:    KSPSetOperators - Sets the matrix associated with the linear system
    446:    and a (possibly) different one associated with the preconditioner.

    448:    Collective on ksp

    450:    Input Parameters:
    451: +  ksp - the KSP context
    452: .  Amat - the matrix that defines the linear system
    453: -  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.

    455:    Notes:

    457:     If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
    458:     space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

    460:     All future calls to KSPSetOperators() must use the same size matrices!

    462:     Passing a NULL for Amat or Pmat removes the matrix that is currently used.

    464:     If you wish to replace either Amat or Pmat but leave the other one untouched then
    465:     first call KSPGetOperators() to get the one you wish to keep, call PetscObjectReference()
    466:     on it and then pass it back in in your call to KSPSetOperators().

    468:     Level: beginner

    470:    Alternative usage: If the operators have NOT been set with KSP/PCSetOperators() then the operators
    471:       are created in PC and returned to the user. In this case, if both operators
    472:       mat and pmat are requested, two DIFFERENT operators will be returned. If
    473:       only one is requested both operators in the PC will be the same (i.e. as
    474:       if one had called KSP/PCSetOperators() with the same argument for both Mats).
    475:       The user must set the sizes of the returned matrices and their type etc just
    476:       as if the user created them with MatCreate(). For example,

    478: $         KSP/PCGetOperators(ksp/pc,&mat,NULL); is equivalent to
    479: $           set size, type, etc of mat

    481: $         MatCreate(comm,&mat);
    482: $         KSP/PCSetOperators(ksp/pc,mat,mat);
    483: $         PetscObjectDereference((PetscObject)mat);
    484: $           set size, type, etc of mat

    486:      and

    488: $         KSP/PCGetOperators(ksp/pc,&mat,&pmat); is equivalent to
    489: $           set size, type, etc of mat and pmat

    491: $         MatCreate(comm,&mat);
    492: $         MatCreate(comm,&pmat);
    493: $         KSP/PCSetOperators(ksp/pc,mat,pmat);
    494: $         PetscObjectDereference((PetscObject)mat);
    495: $         PetscObjectDereference((PetscObject)pmat);
    496: $           set size, type, etc of mat and pmat

    498:     The rational for this support is so that when creating a TS, SNES, or KSP the hierarchy
    499:     of underlying objects (i.e. SNES, KSP, PC, Mat) and their livespans can be completely
    500:     managed by the top most level object (i.e. the TS, SNES, or KSP). Another way to look
    501:     at this is when you create a SNES you do not NEED to create a KSP and attach it to
    502:     the SNES object (the SNES object manages it for you). Similarly when you create a KSP
    503:     you do not need to attach a PC to it (the KSP object manages the PC object for you).
    504:     Thus, why should YOU have to create the Mat and attach it to the SNES/KSP/PC, when
    505:     it can be created for you?

    507: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPGetOperators(), KSPSetComputeOperators(), KSPSetComputeInitialGuess(), KSPSetComputeRHS()
    508: @*/
    509: PetscErrorCode  KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat)
    510: {
    516:   if (!ksp->pc) KSPGetPC(ksp,&ksp->pc);
    517:   PCSetOperators(ksp->pc,Amat,Pmat);
    518:   if (ksp->setupstage == KSP_SETUP_NEWRHS) ksp->setupstage = KSP_SETUP_NEWMATRIX;  /* so that next solve call will call PCSetUp() on new matrix */
    519:   return 0;
    520: }

    522: /*@
    523:    KSPGetOperators - Gets the matrix associated with the linear system
    524:    and a (possibly) different one associated with the preconditioner.

    526:    Collective on ksp

    528:    Input Parameter:
    529: .  ksp - the KSP context

    531:    Output Parameters:
    532: +  Amat - the matrix that defines the linear system
    533: -  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.

    535:     Level: intermediate

    537:    Notes:
    538:     DOES NOT increase the reference counts of the matrix, so you should NOT destroy them.

    540: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPSetOperators(), KSPGetOperatorsSet()
    541: @*/
    542: PetscErrorCode  KSPGetOperators(KSP ksp,Mat *Amat,Mat *Pmat)
    543: {
    545:   if (!ksp->pc) KSPGetPC(ksp,&ksp->pc);
    546:   PCGetOperators(ksp->pc,Amat,Pmat);
    547:   return 0;
    548: }

    550: /*@C
    551:    KSPGetOperatorsSet - Determines if the matrix associated with the linear system and
    552:    possibly a different one associated with the preconditioner have been set in the KSP.

    554:    Not collective, though the results on all processes should be the same

    556:    Input Parameter:
    557: .  pc - the KSP context

    559:    Output Parameters:
    560: +  mat - the matrix associated with the linear system was set
    561: -  pmat - matrix associated with the preconditioner was set, usually the same

    563:    Level: intermediate

    565: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators(), PCGetOperatorsSet()
    566: @*/
    567: PetscErrorCode  KSPGetOperatorsSet(KSP ksp,PetscBool  *mat,PetscBool  *pmat)
    568: {
    570:   if (!ksp->pc) KSPGetPC(ksp,&ksp->pc);
    571:   PCGetOperatorsSet(ksp->pc,mat,pmat);
    572:   return 0;
    573: }

    575: /*@C
    576:    KSPSetPreSolve - Sets a function that is called before every KSPSolve() is started

    578:    Logically Collective on ksp

    580:    Input Parameters:
    581: +   ksp - the solver object
    582: .   presolve - the function to call before the solve
    583: -   prectx - any context needed by the function

    585:    Calling sequence of presolve:
    586: $  func(KSP ksp,Vec rhs,Vec x,void *ctx)

    588: +  ksp - the KSP context
    589: .  rhs - the right-hand side vector
    590: .  x - the solution vector
    591: -  ctx - optional user-provided context

    593:    Level: developer

    595: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPostSolve()
    596: @*/
    597: PetscErrorCode  KSPSetPreSolve(KSP ksp,PetscErrorCode (*presolve)(KSP,Vec,Vec,void*),void *prectx)
    598: {
    600:   ksp->presolve = presolve;
    601:   ksp->prectx   = prectx;
    602:   return 0;
    603: }

    605: /*@C
    606:    KSPSetPostSolve - Sets a function that is called after every KSPSolve() completes (whether it converges or not)

    608:    Logically Collective on ksp

    610:    Input Parameters:
    611: +   ksp - the solver object
    612: .   postsolve - the function to call after the solve
    613: -   postctx - any context needed by the function

    615:    Level: developer

    617:    Calling sequence of postsolve:
    618: $  func(KSP ksp,Vec rhs,Vec x,void *ctx)

    620: +  ksp - the KSP context
    621: .  rhs - the right-hand side vector
    622: .  x - the solution vector
    623: -  ctx - optional user-provided context

    625: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPreSolve()
    626: @*/
    627: PetscErrorCode  KSPSetPostSolve(KSP ksp,PetscErrorCode (*postsolve)(KSP,Vec,Vec,void*),void *postctx)
    628: {
    630:   ksp->postsolve = postsolve;
    631:   ksp->postctx   = postctx;
    632:   return 0;
    633: }

    635: /*@
    636:    KSPCreate - Creates the default KSP context.

    638:    Collective

    640:    Input Parameter:
    641: .  comm - MPI communicator

    643:    Output Parameter:
    644: .  ksp - location to put the KSP context

    646:    Notes:
    647:    The default KSP type is GMRES with a restart of 30, using modified Gram-Schmidt
    648:    orthogonalization.

    650:    Level: beginner

    652: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP
    653: @*/
    654: PetscErrorCode  KSPCreate(MPI_Comm comm,KSP *inksp)
    655: {
    656:   KSP            ksp;
    657:   void           *ctx;

    660:   *inksp = NULL;
    661:   KSPInitializePackage();

    663:   PetscHeaderCreate(ksp,KSP_CLASSID,"KSP","Krylov Method","KSP",comm,KSPDestroy,KSPView);

    665:   ksp->max_it  = 10000;
    666:   ksp->pc_side = ksp->pc_side_set = PC_SIDE_DEFAULT;
    667:   ksp->rtol    = 1.e-5;
    668: #if defined(PETSC_USE_REAL_SINGLE)
    669:   ksp->abstol  = 1.e-25;
    670: #else
    671:   ksp->abstol  = 1.e-50;
    672: #endif
    673:   ksp->divtol  = 1.e4;

    675:   ksp->chknorm        = -1;
    676:   ksp->normtype       = ksp->normtype_set = KSP_NORM_DEFAULT;
    677:   ksp->rnorm          = 0.0;
    678:   ksp->its            = 0;
    679:   ksp->guess_zero     = PETSC_TRUE;
    680:   ksp->calc_sings     = PETSC_FALSE;
    681:   ksp->res_hist       = NULL;
    682:   ksp->res_hist_alloc = NULL;
    683:   ksp->res_hist_len   = 0;
    684:   ksp->res_hist_max   = 0;
    685:   ksp->res_hist_reset = PETSC_TRUE;
    686:   ksp->err_hist       = NULL;
    687:   ksp->err_hist_alloc = NULL;
    688:   ksp->err_hist_len   = 0;
    689:   ksp->err_hist_max   = 0;
    690:   ksp->err_hist_reset = PETSC_TRUE;
    691:   ksp->numbermonitors = 0;
    692:   ksp->numberreasonviews = 0;
    693:   ksp->setfromoptionscalled = 0;
    694:   ksp->nmax = PETSC_DECIDE;

    696:   KSPConvergedDefaultCreate(&ctx);
    697:   KSPSetConvergenceTest(ksp,KSPConvergedDefault,ctx,KSPConvergedDefaultDestroy);
    698:   ksp->ops->buildsolution = KSPBuildSolutionDefault;
    699:   ksp->ops->buildresidual = KSPBuildResidualDefault;

    701:   ksp->vec_sol    = NULL;
    702:   ksp->vec_rhs    = NULL;
    703:   ksp->pc         = NULL;
    704:   ksp->data       = NULL;
    705:   ksp->nwork      = 0;
    706:   ksp->work       = NULL;
    707:   ksp->reason     = KSP_CONVERGED_ITERATING;
    708:   ksp->setupstage = KSP_SETUP_NEW;

    710:   KSPNormSupportTableReset_Private(ksp);

    712:   *inksp = ksp;
    713:   return 0;
    714: }

    716: /*@C
    717:    KSPSetType - Builds KSP for a particular solver.

    719:    Logically Collective on ksp

    721:    Input Parameters:
    722: +  ksp      - the Krylov space context
    723: -  type - a known method

    725:    Options Database Key:
    726: .  -ksp_type  <method> - Sets the method; use -help for a list
    727:     of available methods (for instance, cg or gmres)

    729:    Notes:
    730:    See "petsc/include/petscksp.h" for available methods (for instance,
    731:    KSPCG or KSPGMRES).

    733:   Normally, it is best to use the KSPSetFromOptions() command and
    734:   then set the KSP type from the options database rather than by using
    735:   this routine.  Using the options database provides the user with
    736:   maximum flexibility in evaluating the many different Krylov methods.
    737:   The KSPSetType() routine is provided for those situations where it
    738:   is necessary to set the iterative solver independently of the command
    739:   line or options database.  This might be the case, for example, when
    740:   the choice of iterative solver changes during the execution of the
    741:   program, and the user's application is taking responsibility for
    742:   choosing the appropriate method.  In other words, this routine is
    743:   not for beginners.

    745:   Level: intermediate

    747:   Developer Note: KSPRegister() is used to add Krylov types to KSPList from which they
    748:   are accessed by KSPSetType().

    750: .seealso: PCSetType(), KSPType, KSPRegister(), KSPCreate()

    752: @*/
    753: PetscErrorCode  KSPSetType(KSP ksp, KSPType type)
    754: {
    755:   PetscBool      match;
    756:   PetscErrorCode (*r)(KSP);

    761:   PetscObjectTypeCompare((PetscObject)ksp,type,&match);
    762:   if (match) return 0;

    764:   PetscFunctionListFind(KSPList,type,&r);
    766:   /* Destroy the previous private KSP context */
    767:   if (ksp->ops->destroy) {
    768:     (*ksp->ops->destroy)(ksp);
    769:     ksp->ops->destroy = NULL;
    770:   }
    771:   /* Reinitialize function pointers in KSPOps structure */
    772:   PetscMemzero(ksp->ops,sizeof(struct _KSPOps));
    773:   ksp->ops->buildsolution = KSPBuildSolutionDefault;
    774:   ksp->ops->buildresidual = KSPBuildResidualDefault;
    775:   KSPNormSupportTableReset_Private(ksp);
    776:   ksp->setupnewmatrix     = PETSC_FALSE; // restore default (setup not called in case of new matrix)
    777:   /* Call the KSPCreate_XXX routine for this particular Krylov solver */
    778:   ksp->setupstage = KSP_SETUP_NEW;
    779:   (*r)(ksp);
    780:   PetscObjectChangeTypeName((PetscObject)ksp,type);
    781:   return 0;
    782: }

    784: /*@C
    785:    KSPGetType - Gets the KSP type as a string from the KSP object.

    787:    Not Collective

    789:    Input Parameter:
    790: .  ksp - Krylov context

    792:    Output Parameter:
    793: .  name - name of KSP method

    795:    Level: intermediate

    797: .seealso: KSPSetType()
    798: @*/
    799: PetscErrorCode  KSPGetType(KSP ksp,KSPType *type)
    800: {
    803:   *type = ((PetscObject)ksp)->type_name;
    804:   return 0;
    805: }

    807: /*@C
    808:   KSPRegister -  Adds a method to the Krylov subspace solver package.

    810:    Not Collective

    812:    Input Parameters:
    813: +  name_solver - name of a new user-defined solver
    814: -  routine_create - routine to create method context

    816:    Notes:
    817:    KSPRegister() may be called multiple times to add several user-defined solvers.

    819:    Sample usage:
    820: .vb
    821:    KSPRegister("my_solver",MySolverCreate);
    822: .ve

    824:    Then, your solver can be chosen with the procedural interface via
    825: $     KSPSetType(ksp,"my_solver")
    826:    or at runtime via the option
    827: $     -ksp_type my_solver

    829:    Level: advanced

    831: .seealso: KSPRegisterAll()
    832: @*/
    833: PetscErrorCode  KSPRegister(const char sname[],PetscErrorCode (*function)(KSP))
    834: {
    835:   KSPInitializePackage();
    836:   PetscFunctionListAdd(&KSPList,sname,function);
    837:   return 0;
    838: }

    840: PetscErrorCode KSPMonitorMakeKey_Internal(const char name[], PetscViewerType vtype, PetscViewerFormat format, char key[])
    841: {
    842:   PetscStrncpy(key, name, PETSC_MAX_PATH_LEN);
    843:   PetscStrlcat(key, ":", PETSC_MAX_PATH_LEN);
    844:   PetscStrlcat(key, vtype, PETSC_MAX_PATH_LEN);
    845:   PetscStrlcat(key, ":", PETSC_MAX_PATH_LEN);
    846:   PetscStrlcat(key, PetscViewerFormats[format], PETSC_MAX_PATH_LEN);
    847:   return 0;
    848: }

    850: /*@C
    851:   KSPMonitorRegister -  Adds Krylov subspace solver monitor routine.

    853:   Not Collective

    855:   Input Parameters:
    856: + name    - name of a new monitor routine
    857: . vtype   - A PetscViewerType for the output
    858: . format  - A PetscViewerFormat for the output
    859: . monitor - Monitor routine
    860: . create  - Creation routine, or NULL
    861: - destroy - Destruction routine, or NULL

    863:   Notes:
    864:   KSPMonitorRegister() may be called multiple times to add several user-defined monitors.

    866:   Sample usage:
    867: .vb
    868:   KSPMonitorRegister("my_monitor",PETSCVIEWERASCII,PETSC_VIEWER_ASCII_INFO_DETAIL,MyMonitor,NULL,NULL);
    869: .ve

    871:   Then, your monitor can be chosen with the procedural interface via
    872: $     KSPMonitorSetFromOptions(ksp,"-ksp_monitor_my_monitor","my_monitor",NULL)
    873:   or at runtime via the option
    874: $     -ksp_monitor_my_monitor

    876:    Level: advanced

    878: .seealso: KSPMonitorRegisterAll()
    879: @*/
    880: PetscErrorCode KSPMonitorRegister(const char name[], PetscViewerType vtype, PetscViewerFormat format,
    881:                                   PetscErrorCode (*monitor)(KSP, PetscInt, PetscReal, PetscViewerAndFormat *),
    882:                                   PetscErrorCode (*create)(PetscViewer, PetscViewerFormat, void *, PetscViewerAndFormat **),
    883:                                   PetscErrorCode (*destroy)(PetscViewerAndFormat **))
    884: {
    885:   char           key[PETSC_MAX_PATH_LEN];

    887:   KSPInitializePackage();
    888:   KSPMonitorMakeKey_Internal(name, vtype, format, key);
    889:   PetscFunctionListAdd(&KSPMonitorList, key, monitor);
    890:   if (create)  PetscFunctionListAdd(&KSPMonitorCreateList,  key, create);
    891:   if (destroy) PetscFunctionListAdd(&KSPMonitorDestroyList, key, destroy);
    892:   return 0;
    893: }