Actual source code: itcreate.c
petsc-3.15.0 2021-03-30
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      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: {
     55:   PetscBool      isbinary;
     56:   PetscInt       classid;
     57:   char           type[256];
     58:   PC             pc;

     63:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
     64:   if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");

     66:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
     67:   if (classid != KSP_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)newdm),PETSC_ERR_ARG_WRONG,"Not KSP next in file");
     68:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
     69:   KSPSetType(newdm, type);
     70:   if (newdm->ops->load) {
     71:     (*newdm->ops->load)(newdm,viewer);
     72:   }
     73:   KSPGetPC(newdm,&pc);
     74:   PCLoad(pc,viewer);
     75:   return(0);
     76: }

     78: #include <petscdraw.h>
     79: #if defined(PETSC_HAVE_SAWS)
     80: #include <petscviewersaws.h>
     81: #endif
     82: /*@C
     83:    KSPView - Prints the KSP data structure.

     85:    Collective on ksp

     87:    Input Parameters:
     88: +  ksp - the Krylov space context
     89: -  viewer - visualization context

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

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

    102:    The available formats include
    103: +     PETSC_VIEWER_DEFAULT - standard output (default)
    104: -     PETSC_VIEWER_ASCII_INFO_DETAIL - more verbose output for PCBJACOBI and PCASM

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

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

    111:    Level: beginner

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

    125:   if (!viewer) {
    126:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ksp),&viewer);
    127:   }

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

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

    193:     PetscViewerDrawGetDraw(viewer,0,&draw);
    194:     PetscDrawGetCurrentPoint(draw,&x,&y);
    195:     PetscObjectTypeCompare((PetscObject)ksp,KSPPREONLY,&flg);
    196:     if (!flg) {
    197:       PetscStrncpy(str,"KSP: ",sizeof(str));
    198:       PetscStrlcat(str,((PetscObject)ksp)->type_name,sizeof(str));
    199:       PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_RED,PETSC_DRAW_BLACK,str,NULL,&h);
    200:       bottom = y - h;
    201:     } else {
    202:       bottom = y;
    203:     }
    204:     PetscDrawPushCurrentPoint(draw,x,bottom);
    205: #if defined(PETSC_HAVE_SAWS)
    206:   } else if (issaws) {
    207:     PetscMPIInt rank;
    208:     const char  *name;

    210:     PetscObjectGetName((PetscObject)ksp,&name);
    211:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
    212:     if (!((PetscObject)ksp)->amsmem && !rank) {
    213:       char       dir[1024];

    215:       PetscObjectViewSAWs((PetscObject)ksp,viewer);
    216:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
    217:       PetscStackCallSAWs(SAWs_Register,(dir,&ksp->its,1,SAWs_READ,SAWs_INT));
    218:       if (!ksp->res_hist) {
    219:         KSPSetResidualHistory(ksp,NULL,PETSC_DECIDE,PETSC_TRUE);
    220:       }
    221:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/res_hist",name);
    222:       PetscStackCallSAWs(SAWs_Register,(dir,ksp->res_hist,10,SAWs_READ,SAWs_DOUBLE));
    223:     }
    224: #endif
    225:   } else if (ksp->ops->view) {
    226:     (*ksp->ops->view)(ksp,viewer);
    227:   }
    228:   if (ksp->pc) {
    229:     PCView(ksp->pc,viewer);
    230:   }
    231:   if (isdraw) {
    232:     PetscDraw draw;
    233:     PetscViewerDrawGetDraw(viewer,0,&draw);
    234:     PetscDrawPopCurrentPoint(draw);
    235:   }
    236:   return(0);
    237: }

    239: /*@C
    240:    KSPViewFromOptions - View from Options

    242:    Collective on KSP

    244:    Input Parameters:
    245: +  A - Krylov solver context
    246: .  obj - Optional object
    247: -  name - command line option

    249:    Level: intermediate
    250: .seealso:  KSP, KSPView, PetscObjectViewFromOptions(), KSPCreate()
    251: @*/
    252: PetscErrorCode  KSPViewFromOptions(KSP A,PetscObject obj,const char name[])
    253: {

    258:   PetscObjectViewFromOptions((PetscObject)A,obj,name);
    259:   return(0);
    260: }

    262: /*@
    263:    KSPSetNormType - Sets the norm that is used for convergence testing.

    265:    Logically Collective on ksp

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

    282:    Options Database Key:
    283: .   -ksp_norm_type <none,preconditioned,unpreconditioned,natural>

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

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

    293:    Level: advanced

    295: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetCheckNormIteration(), KSPSetPCSide(), KSPGetPCSide(), KSPNormType
    296: @*/
    297: PetscErrorCode  KSPSetNormType(KSP ksp,KSPNormType normtype)
    298: {
    302:   ksp->normtype = ksp->normtype_set = normtype;
    303:   return(0);
    304: }

    306: /*@
    307:    KSPSetCheckNormIteration - Sets the first iteration at which the norm of the residual will be
    308:      computed and used in the convergence test.

    310:    Logically Collective on ksp

    312:    Input Parameter:
    313: +  ksp - Krylov solver context
    314: -  it  - use -1 to check at all iterations

    316:    Notes:
    317:    Currently only works with KSPCG, KSPBCGS and KSPIBCGS

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

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

    325: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType()
    326: @*/
    327: PetscErrorCode  KSPSetCheckNormIteration(KSP ksp,PetscInt it)
    328: {
    332:   ksp->chknorm = it;
    333:   return(0);
    334: }

    336: /*@
    337:    KSPSetLagNorm - Lags the residual norm calculation so that it is computed as part of the MPI_Allreduce() for
    338:    computing the inner products for the next iteration.  This can reduce communication costs at the expense of doing
    339:    one additional iteration.

    342:    Logically Collective on ksp

    344:    Input Parameter:
    345: +  ksp - Krylov solver context
    346: -  flg - PETSC_TRUE or PETSC_FALSE

    348:    Options Database Keys:
    349: .  -ksp_lag_norm - lag the calculated residual norm

    351:    Notes:
    352:    Currently only works with KSPIBCGS.

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

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

    359: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSPConvergedSkip(), KSPSetNormType(), KSPSetCheckNormIteration()
    360: @*/
    361: PetscErrorCode  KSPSetLagNorm(KSP ksp,PetscBool flg)
    362: {
    366:   ksp->lagnorm = flg;
    367:   return(0);
    368: }

    370: /*@
    371:    KSPSetSupportedNorm - Sets a norm and preconditioner side supported by a KSP

    373:    Logically Collective

    375:    Input Arguments:
    376: +  ksp - Krylov method
    377: .  normtype - supported norm type
    378: .  pcside - preconditioner side that can be used with this norm
    379: -  priority - positive integer preference for this combination; larger values have higher priority

    381:    Level: developer

    383:    Notes:
    384:    This function should be called from the implementation files KSPCreate_XXX() to declare
    385:    which norms and preconditioner sides are supported. Users should not need to call this
    386:    function.

    388: .seealso: KSPSetNormType(), KSPSetPCSide()
    389: @*/
    390: PetscErrorCode KSPSetSupportedNorm(KSP ksp,KSPNormType normtype,PCSide pcside,PetscInt priority)
    391: {

    395:   ksp->normsupporttable[normtype][pcside] = priority;
    396:   return(0);
    397: }

    399: PetscErrorCode KSPNormSupportTableReset_Private(KSP ksp)
    400: {

    404:   PetscMemzero(ksp->normsupporttable,sizeof(ksp->normsupporttable));
    405:   ksp->pc_side  = ksp->pc_side_set;
    406:   ksp->normtype = ksp->normtype_set;
    407:   return(0);
    408: }

    410: PetscErrorCode KSPSetUpNorms_Private(KSP ksp,PetscBool errorifnotsupported,KSPNormType *normtype,PCSide *pcside)
    411: {
    412:   PetscInt i,j,best,ibest = 0,jbest = 0;

    415:   best = 0;
    416:   for (i=0; i<KSP_NORM_MAX; i++) {
    417:     for (j=0; j<PC_SIDE_MAX; j++) {
    418:       if ((ksp->normtype == KSP_NORM_DEFAULT || ksp->normtype == i) && (ksp->pc_side == PC_SIDE_DEFAULT || ksp->pc_side == j) && (ksp->normsupporttable[i][j] > best)) {
    419:         best  = ksp->normsupporttable[i][j];
    420:         ibest = i;
    421:         jbest = j;
    422:       }
    423:     }
    424:   }
    425:   if (best < 1 && errorifnotsupported) {
    426:     if (ksp->normtype == KSP_NORM_DEFAULT && ksp->pc_side == PC_SIDE_DEFAULT) SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_PLIB,"The %s KSP implementation did not call KSPSetSupportedNorm()",((PetscObject)ksp)->type_name);
    427:     if (ksp->normtype == KSP_NORM_DEFAULT) SETERRQ2(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"KSP %s does not support %s",((PetscObject)ksp)->type_name,PCSides[ksp->pc_side]);
    428:     if (ksp->pc_side == PC_SIDE_DEFAULT) SETERRQ2(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"KSP %s does not support %s",((PetscObject)ksp)->type_name,KSPNormTypes[ksp->normtype]);
    429:     SETERRQ3(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]);
    430:   }
    431:   if (normtype) *normtype = (KSPNormType)ibest;
    432:   if (pcside)   *pcside   = (PCSide)jbest;
    433:   return(0);
    434: }

    436: /*@
    437:    KSPGetNormType - Gets the norm that is used for convergence testing.

    439:    Not Collective

    441:    Input Parameter:
    442: .  ksp - Krylov solver context

    444:    Output Parameter:
    445: .  normtype - norm that is used for convergence testing

    447:    Level: advanced

    449: .seealso: KSPNormType, KSPSetNormType(), KSPConvergedSkip()
    450: @*/
    451: PetscErrorCode  KSPGetNormType(KSP ksp, KSPNormType *normtype)
    452: {

    458:   KSPSetUpNorms_Private(ksp,PETSC_TRUE,&ksp->normtype,&ksp->pc_side);
    459:   *normtype = ksp->normtype;
    460:   return(0);
    461: }

    463: #if defined(PETSC_HAVE_SAWS)
    464: #include <petscviewersaws.h>
    465: #endif

    467: /*@
    468:    KSPSetOperators - Sets the matrix associated with the linear system
    469:    and a (possibly) different one associated with the preconditioner.

    471:    Collective on ksp

    473:    Input Parameters:
    474: +  ksp - the KSP context
    475: .  Amat - the matrix that defines the linear system
    476: -  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.

    478:    Notes:

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

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

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

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

    491:     Level: beginner

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

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

    504: $         MatCreate(comm,&mat);
    505: $         KSP/PCSetOperators(ksp/pc,mat,mat);
    506: $         PetscObjectDereference((PetscObject)mat);
    507: $           set size, type, etc of mat

    509:      and

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

    514: $         MatCreate(comm,&mat);
    515: $         MatCreate(comm,&pmat);
    516: $         KSP/PCSetOperators(ksp/pc,mat,pmat);
    517: $         PetscObjectDereference((PetscObject)mat);
    518: $         PetscObjectDereference((PetscObject)pmat);
    519: $           set size, type, etc of mat and pmat

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

    530: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPGetOperators(), KSPSetComputeOperators(), KSPSetComputeInitialGuess(), KSPSetComputeRHS()
    531: @*/
    532: PetscErrorCode  KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat)
    533: {

    542:   if (!ksp->pc) {KSPGetPC(ksp,&ksp->pc);}
    543:   PCSetOperators(ksp->pc,Amat,Pmat);
    544:   if (ksp->setupstage == KSP_SETUP_NEWRHS) ksp->setupstage = KSP_SETUP_NEWMATRIX;  /* so that next solve call will call PCSetUp() on new matrix */
    545:   return(0);
    546: }

    548: /*@
    549:    KSPGetOperators - Gets the matrix associated with the linear system
    550:    and a (possibly) different one associated with the preconditioner.

    552:    Collective on ksp

    554:    Input Parameter:
    555: .  ksp - the KSP context

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

    561:     Level: intermediate

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

    566: .seealso: KSPSolve(), KSPGetPC(), PCGetOperators(), PCSetOperators(), KSPSetOperators(), KSPGetOperatorsSet()
    567: @*/
    568: PetscErrorCode  KSPGetOperators(KSP ksp,Mat *Amat,Mat *Pmat)
    569: {

    574:   if (!ksp->pc) {KSPGetPC(ksp,&ksp->pc);}
    575:   PCGetOperators(ksp->pc,Amat,Pmat);
    576:   return(0);
    577: }

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

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

    585:    Input Parameter:
    586: .  pc - the KSP context

    588:    Output Parameters:
    589: +  mat - the matrix associated with the linear system was set
    590: -  pmat - matrix associated with the preconditioner was set, usually the same

    592:    Level: intermediate

    594: .seealso: PCSetOperators(), KSPGetOperators(), KSPSetOperators(), PCGetOperators(), PCGetOperatorsSet()
    595: @*/
    596: PetscErrorCode  KSPGetOperatorsSet(KSP ksp,PetscBool  *mat,PetscBool  *pmat)
    597: {

    602:   if (!ksp->pc) {KSPGetPC(ksp,&ksp->pc);}
    603:   PCGetOperatorsSet(ksp->pc,mat,pmat);
    604:   return(0);
    605: }

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

    610:    Logically Collective on ksp

    612:    Input Parameters:
    613: +   ksp - the solver object
    614: .   presolve - the function to call before the solve
    615: -   prectx - any context needed by the function

    617:    Calling sequence of presolve:
    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:    Level: developer

    627: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPostSolve()
    628: @*/
    629: PetscErrorCode  KSPSetPreSolve(KSP ksp,PetscErrorCode (*presolve)(KSP,Vec,Vec,void*),void *prectx)
    630: {
    633:   ksp->presolve = presolve;
    634:   ksp->prectx   = prectx;
    635:   return(0);
    636: }

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

    641:    Logically Collective on ksp

    643:    Input Parameters:
    644: +   ksp - the solver object
    645: .   postsolve - the function to call after the solve
    646: -   postctx - any context needed by the function

    648:    Level: developer

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

    653: +  ksp - the KSP context
    654: .  rhs - the right-hand side vector
    655: .  x - the solution vector
    656: -  ctx - optional user-provided context

    658: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP, KSPSetPreSolve()
    659: @*/
    660: PetscErrorCode  KSPSetPostSolve(KSP ksp,PetscErrorCode (*postsolve)(KSP,Vec,Vec,void*),void *postctx)
    661: {
    664:   ksp->postsolve = postsolve;
    665:   ksp->postctx   = postctx;
    666:   return(0);
    667: }

    669: /*@
    670:    KSPCreate - Creates the default KSP context.

    672:    Collective

    674:    Input Parameter:
    675: .  comm - MPI communicator

    677:    Output Parameter:
    678: .  ksp - location to put the KSP context

    680:    Notes:
    681:    The default KSP type is GMRES with a restart of 30, using modified Gram-Schmidt
    682:    orthogonalization.

    684:    Level: beginner

    686: .seealso: KSPSetUp(), KSPSolve(), KSPDestroy(), KSP
    687: @*/
    688: PetscErrorCode  KSPCreate(MPI_Comm comm,KSP *inksp)
    689: {
    690:   KSP            ksp;
    692:   void           *ctx;

    696:   *inksp = NULL;
    697:   KSPInitializePackage();

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

    701:   ksp->max_it  = 10000;
    702:   ksp->pc_side = ksp->pc_side_set = PC_SIDE_DEFAULT;
    703:   ksp->rtol    = 1.e-5;
    704: #if defined(PETSC_USE_REAL_SINGLE)
    705:   ksp->abstol  = 1.e-25;
    706: #else
    707:   ksp->abstol  = 1.e-50;
    708: #endif
    709:   ksp->divtol  = 1.e4;

    711:   ksp->chknorm        = -1;
    712:   ksp->normtype       = ksp->normtype_set = KSP_NORM_DEFAULT;
    713:   ksp->rnorm          = 0.0;
    714:   ksp->its            = 0;
    715:   ksp->guess_zero     = PETSC_TRUE;
    716:   ksp->calc_sings     = PETSC_FALSE;
    717:   ksp->res_hist       = NULL;
    718:   ksp->res_hist_alloc = NULL;
    719:   ksp->res_hist_len   = 0;
    720:   ksp->res_hist_max   = 0;
    721:   ksp->res_hist_reset = PETSC_TRUE;
    722:   ksp->err_hist       = NULL;
    723:   ksp->err_hist_alloc = NULL;
    724:   ksp->err_hist_len   = 0;
    725:   ksp->err_hist_max   = 0;
    726:   ksp->err_hist_reset = PETSC_TRUE;
    727:   ksp->numbermonitors = 0;
    728:   ksp->numberreasonviews = 0;
    729:   ksp->setfromoptionscalled = 0;
    730:   ksp->nmax = PETSC_DECIDE;

    732:   KSPConvergedDefaultCreate(&ctx);
    733:   KSPSetConvergenceTest(ksp,KSPConvergedDefault,ctx,KSPConvergedDefaultDestroy);
    734:   ksp->ops->buildsolution = KSPBuildSolutionDefault;
    735:   ksp->ops->buildresidual = KSPBuildResidualDefault;

    737:   ksp->vec_sol    = NULL;
    738:   ksp->vec_rhs    = NULL;
    739:   ksp->pc         = NULL;
    740:   ksp->data       = NULL;
    741:   ksp->nwork      = 0;
    742:   ksp->work       = NULL;
    743:   ksp->reason     = KSP_CONVERGED_ITERATING;
    744:   ksp->setupstage = KSP_SETUP_NEW;

    746:   KSPNormSupportTableReset_Private(ksp);

    748:   *inksp = ksp;
    749:   return(0);
    750: }

    752: /*@C
    753:    KSPSetType - Builds KSP for a particular solver.

    755:    Logically Collective on ksp

    757:    Input Parameters:
    758: +  ksp      - the Krylov space context
    759: -  type - a known method

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

    765:    Notes:
    766:    See "petsc/include/petscksp.h" for available methods (for instance,
    767:    KSPCG or KSPGMRES).

    769:   Normally, it is best to use the KSPSetFromOptions() command and
    770:   then set the KSP type from the options database rather than by using
    771:   this routine.  Using the options database provides the user with
    772:   maximum flexibility in evaluating the many different Krylov methods.
    773:   The KSPSetType() routine is provided for those situations where it
    774:   is necessary to set the iterative solver independently of the command
    775:   line or options database.  This might be the case, for example, when
    776:   the choice of iterative solver changes during the execution of the
    777:   program, and the user's application is taking responsibility for
    778:   choosing the appropriate method.  In other words, this routine is
    779:   not for beginners.

    781:   Level: intermediate

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

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

    788: @*/
    789: PetscErrorCode  KSPSetType(KSP ksp, KSPType type)
    790: {
    791:   PetscErrorCode ierr,(*r)(KSP);
    792:   PetscBool      match;

    798:   PetscObjectTypeCompare((PetscObject)ksp,type,&match);
    799:   if (match) return(0);

    801:   PetscFunctionListFind(KSPList,type,&r);
    802:   if (!r) SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested KSP type %s",type);
    803:   /* Destroy the previous private KSP context */
    804:   if (ksp->ops->destroy) {
    805:     (*ksp->ops->destroy)(ksp);
    806:     ksp->ops->destroy = NULL;
    807:   }
    808:   /* Reinitialize function pointers in KSPOps structure */
    809:   PetscMemzero(ksp->ops,sizeof(struct _KSPOps));
    810:   ksp->ops->buildsolution = KSPBuildSolutionDefault;
    811:   ksp->ops->buildresidual = KSPBuildResidualDefault;
    812:   KSPNormSupportTableReset_Private(ksp);
    813:   ksp->setupnewmatrix     = PETSC_FALSE; // restore default (setup not called in case of new matrix)
    814:   /* Call the KSPCreate_XXX routine for this particular Krylov solver */
    815:   ksp->setupstage = KSP_SETUP_NEW;
    816:   (*r)(ksp);
    817:   PetscObjectChangeTypeName((PetscObject)ksp,type);
    818:   return(0);
    819: }

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

    824:    Not Collective

    826:    Input Parameter:
    827: .  ksp - Krylov context

    829:    Output Parameter:
    830: .  name - name of KSP method

    832:    Level: intermediate

    834: .seealso: KSPSetType()
    835: @*/
    836: PetscErrorCode  KSPGetType(KSP ksp,KSPType *type)
    837: {
    841:   *type = ((PetscObject)ksp)->type_name;
    842:   return(0);
    843: }

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

    848:    Not Collective

    850:    Input Parameters:
    851: +  name_solver - name of a new user-defined solver
    852: -  routine_create - routine to create method context

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

    857:    Sample usage:
    858: .vb
    859:    KSPRegister("my_solver",MySolverCreate);
    860: .ve

    862:    Then, your solver can be chosen with the procedural interface via
    863: $     KSPSetType(ksp,"my_solver")
    864:    or at runtime via the option
    865: $     -ksp_type my_solver

    867:    Level: advanced

    869: .seealso: KSPRegisterAll()
    870: @*/
    871: PetscErrorCode  KSPRegister(const char sname[],PetscErrorCode (*function)(KSP))
    872: {

    876:   KSPInitializePackage();
    877:   PetscFunctionListAdd(&KSPList,sname,function);
    878:   return(0);
    879: }

    881: PetscErrorCode KSPMonitorMakeKey_Internal(const char name[], PetscViewerType vtype, PetscViewerFormat format, char key[])
    882: {

    886:   PetscStrncpy(key, name, PETSC_MAX_PATH_LEN);
    887:   PetscStrlcat(key, ":", PETSC_MAX_PATH_LEN);
    888:   PetscStrlcat(key, vtype, PETSC_MAX_PATH_LEN);
    889:   PetscStrlcat(key, ":", PETSC_MAX_PATH_LEN);
    890:   PetscStrlcat(key, PetscViewerFormats[format], PETSC_MAX_PATH_LEN);
    891:   return(0);
    892: }

    894: /*@C
    895:   KSPMonitorRegister -  Adds Krylov subspace solver monitor routine.

    897:   Not Collective

    899:   Input Parameters:
    900: + name    - name of a new monitor routine
    901: . vtype   - A PetscViewerType for the output
    902: . format  - A PetscViewerFormat for the output
    903: . monitor - Monitor routine
    904: . create  - Creation routine, or NULL
    905: - destroy - Destruction routine, or NULL

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

    910:   Sample usage:
    911: .vb
    912:   KSPMonitorRegister("my_monitor",PETSCVIEWERASCII,PETSC_VIEWER_ASCII_INFO_DETAIL,MyMonitor,NULL,NULL);
    913: .ve

    915:   Then, your monitor can be chosen with the procedural interface via
    916: $     KSPMonitorSetFromOptions(ksp,"-ksp_monitor_my_monitor","my_monitor",NULL)
    917:   or at runtime via the option
    918: $     -ksp_monitor_my_monitor

    920:    Level: advanced

    922: .seealso: KSPMonitorRegisterAll()
    923: @*/
    924: PetscErrorCode KSPMonitorRegister(const char name[], PetscViewerType vtype, PetscViewerFormat format,
    925:                                   PetscErrorCode (*monitor)(KSP, PetscInt, PetscReal, PetscViewerAndFormat *),
    926:                                   PetscErrorCode (*create)(PetscViewer, PetscViewerFormat, void *, PetscViewerAndFormat **),
    927:                                   PetscErrorCode (*destroy)(PetscViewerAndFormat **))
    928: {
    929:   char           key[PETSC_MAX_PATH_LEN];

    933:   KSPInitializePackage();
    934:   KSPMonitorMakeKey_Internal(name, vtype, format, key);
    935:   PetscFunctionListAdd(&KSPMonitorList, key, monitor);
    936:   if (create)  {PetscFunctionListAdd(&KSPMonitorCreateList,  key, create);}
    937:   if (destroy) {PetscFunctionListAdd(&KSPMonitorDestroyList, key, destroy);}
    938:   return(0);
    939: }