Date: 2022-03-31T04:47:56+00:00

Actual source code: pcset.c

      2: /*
      3:     Routines to set PC methods and options.
      4: */

      6: #include <petsc/private/pcimpl.h>
      7: #include <petscdm.h>

      9: PetscBool PCRegisterAllCalled = PETSC_FALSE;
     10: /*
     11:    Contains the list of registered PC routines
     12: */
     13: PetscFunctionList PCList = NULL;

     15: /*@C
     16:    PCSetType - Builds PC for a particular preconditioner type

     18:    Collective on PC

     20:    Input Parameters:
     21: +  pc - the preconditioner context.
     22: -  type - a known method

     24:    Options Database Key:
     25: .  -pc_type <type> - Sets PC type

     27:    Use -help for a list of available methods (for instance,
     28:    jacobi or bjacobi)

     30:   Notes:
     31:   See "petsc/include/petscpc.h" for available methods (for instance,
     32:   PCJACOBI, PCILU, or PCBJACOBI).

     34:   Normally, it is best to use the KSPSetFromOptions() command and
     35:   then set the PC type from the options database rather than by using
     36:   this routine.  Using the options database provides the user with
     37:   maximum flexibility in evaluating the many different preconditioners.
     38:   The PCSetType() routine is provided for those situations where it
     39:   is necessary to set the preconditioner independently of the command
     40:   line or options database.  This might be the case, for example, when
     41:   the choice of preconditioner changes during the execution of the
     42:   program, and the user's application is taking responsibility for
     43:   choosing the appropriate preconditioner.  In other words, this
     44:   routine is not for beginners.

     46:   Level: intermediate

     48:   Developer Note: PCRegister() is used to add preconditioner types to PCList from which they
     49:   are accessed by PCSetType().

     51: .seealso: KSPSetType(), PCType, PCRegister(), PCCreate(), KSPGetPC()

     53: @*/
     54: PetscErrorCode  PCSetType(PC pc,PCType type)
     55: {
     56:   PetscBool      match;
     57:   PetscErrorCode (*r)(PC);

     62:   PetscObjectTypeCompare((PetscObject)pc,type,&match);
     63:   if (match) return 0;

     65:   PetscFunctionListFind(PCList,type,&r);
     67:   /* Destroy the previous private PC context */
     68:   if (pc->ops->destroy) {
     69:     (*pc->ops->destroy)(pc);
     70:     pc->ops->destroy = NULL;
     71:     pc->data         = NULL;
     72:   }
     73:   PetscFunctionListDestroy(&((PetscObject)pc)->qlist);
     74:   /* Reinitialize function pointers in PCOps structure */
     75:   PetscMemzero(pc->ops,sizeof(struct _PCOps));
     76:   /* XXX Is this OK?? */
     77:   pc->modifysubmatrices  = NULL;
     78:   pc->modifysubmatricesP = NULL;
     79:   /* Call the PCCreate_XXX routine for this particular preconditioner */
     80:   pc->setupcalled = 0;

     82:   PetscObjectChangeTypeName((PetscObject)pc,type);
     83:   (*r)(pc);
     84:   return 0;
     85: }

     87: /*@C
     88:    PCGetType - Gets the PC method type and name (as a string) from the PC
     89:    context.

     91:    Not Collective

     93:    Input Parameter:
     94: .  pc - the preconditioner context

     96:    Output Parameter:
     97: .  type - name of preconditioner method

     99:    Level: intermediate

    101: .seealso: PCSetType()

    103: @*/
    104: PetscErrorCode  PCGetType(PC pc,PCType *type)
    105: {
    108:   *type = ((PetscObject)pc)->type_name;
    109:   return 0;
    110: }

    112: extern PetscErrorCode PCGetDefaultType_Private(PC,const char*[]);

    114: /*@
    115:    PCSetFromOptions - Sets PC options from the options database.
    116:    This routine must be called before PCSetUp() if the user is to be
    117:    allowed to set the preconditioner method.

    119:    Collective on PC

    121:    Input Parameter:
    122: .  pc - the preconditioner context

    124:    Options Database:
    125: .   -pc_use_amat true,false - see PCSetUseAmat()

    127:    Level: developer

    129: .seealso: PCSetUseAmat()

    131: @*/
    132: PetscErrorCode  PCSetFromOptions(PC pc)
    133: {
    135:   char           type[256];
    136:   const char     *def;
    137:   PetscBool      flg;

    141:   PCRegisterAll();
    142:   PetscObjectOptionsBegin((PetscObject)pc);
    143:   if (!((PetscObject)pc)->type_name) {
    144:     PCGetDefaultType_Private(pc,&def);
    145:   } else {
    146:     def = ((PetscObject)pc)->type_name;
    147:   }

    149:   PetscOptionsFList("-pc_type","Preconditioner","PCSetType",PCList,def,type,256,&flg);
    150:   if (flg) {
    151:     PCSetType(pc,type);
    152:   } else if (!((PetscObject)pc)->type_name) {
    153:     PCSetType(pc,def);
    154:   }

    156:   PetscObjectTypeCompare((PetscObject)pc,PCNONE,&flg);
    157:   if (flg) goto skipoptions;

    159:   PetscOptionsBool("-pc_use_amat","use Amat (instead of Pmat) to define preconditioner in nested inner solves","PCSetUseAmat",pc->useAmat,&pc->useAmat,NULL);

    161:   if (pc->ops->setfromoptions) {
    162:     (*pc->ops->setfromoptions)(PetscOptionsObject,pc);
    163:   }

    165:   skipoptions:
    166:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
    167:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)pc);
    168:   PetscOptionsEnd();
    169:   pc->setfromoptionscalled++;
    170:   return 0;
    171: }

    173: /*@
    174:    PCSetDM - Sets the DM that may be used by some preconditioners

    176:    Logically Collective on PC

    178:    Input Parameters:
    179: +  pc - the preconditioner context
    180: -  dm - the dm, can be NULL

    182:    Level: intermediate

    184:    Developer Notes:
    185:     The routines KSP/SNES/TSSetDM() require the dm to be non-NULL, but this one can be NULL since all it does is
    186:     replace the current DM

    188: .seealso: PCGetDM(), KSPSetDM(), KSPGetDM()
    189: @*/
    190: PetscErrorCode  PCSetDM(PC pc,DM dm)
    191: {
    193:   if (dm) PetscObjectReference((PetscObject)dm);
    194:   DMDestroy(&pc->dm);
    195:   pc->dm = dm;
    196:   return 0;
    197: }

    199: /*@
    200:    PCGetDM - Gets the DM that may be used by some preconditioners

    202:    Not Collective

    204:    Input Parameter:
    205: . pc - the preconditioner context

    207:    Output Parameter:
    208: .  dm - the dm

    210:    Level: intermediate

    212: .seealso: PCSetDM(), KSPSetDM(), KSPGetDM()
    213: @*/
    214: PetscErrorCode  PCGetDM(PC pc,DM *dm)
    215: {
    217:   *dm = pc->dm;
    218:   return 0;
    219: }

    221: /*@
    222:    PCSetApplicationContext - Sets the optional user-defined context for the linear solver.

    224:    Logically Collective on PC

    226:    Input Parameters:
    227: +  pc - the PC context
    228: -  usrP - optional user context

    230:    Level: intermediate

    232: .seealso: PCGetApplicationContext()
    233: @*/
    234: PetscErrorCode  PCSetApplicationContext(PC pc,void *usrP)
    235: {
    237:   pc->user = usrP;
    238:   return 0;
    239: }

    241: /*@
    242:    PCGetApplicationContext - Gets the user-defined context for the linear solver.

    244:    Not Collective

    246:    Input Parameter:
    247: .  pc - PC context

    249:    Output Parameter:
    250: .  usrP - user context

    252:    Level: intermediate

    254: .seealso: PCSetApplicationContext()
    255: @*/
    256: PetscErrorCode  PCGetApplicationContext(PC pc,void *usrP)
    257: {
    259:   *(void**)usrP = pc->user;
    260:   return 0;
    261: }