Date: 2022-03-04T17:38:50+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:   PetscErrorCode ierr,(*r)(PC);
     57:   PetscBool      match;

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

     66:    PetscFunctionListFind(PCList,type,&r);
     67:   if (!r) SETERRQ1(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested PC type %s",type);
     68:   /* Destroy the previous private PC context */
     69:   if (pc->ops->destroy) {
     70:     (*pc->ops->destroy)(pc);
     71:     pc->ops->destroy = NULL;
     72:     pc->data         = NULL;
     73:   }
     74:   PetscFunctionListDestroy(&((PetscObject)pc)->qlist);
     75:   /* Reinitialize function pointers in PCOps structure */
     76:   PetscMemzero(pc->ops,sizeof(struct _PCOps));
     77:   /* XXX Is this OK?? */
     78:   pc->modifysubmatrices  = NULL;
     79:   pc->modifysubmatricesP = NULL;
     80:   /* Call the PCCreate_XXX routine for this particular preconditioner */
     81:   pc->setupcalled = 0;

     83:   PetscObjectChangeTypeName((PetscObject)pc,type);
     84:   (*r)(pc);
     85:   return(0);
     86: }

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

     92:    Not Collective

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

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

    100:    Level: intermediate

    102: .seealso: PCSetType()

    104: @*/
    105: PetscErrorCode  PCGetType(PC pc,PCType *type)
    106: {
    110:   *type = ((PetscObject)pc)->type_name;
    111:   return(0);
    112: }

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

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

    121:    Collective on PC

    123:    Input Parameter:
    124: .  pc - the preconditioner context

    126:    Options Database:
    127: .   -pc_use_amat true,false see PCSetUseAmat()

    129:    Level: developer

    131: .seealso: PCSetUseAmat()

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

    144:   PCRegisterAll();
    145:   PetscObjectOptionsBegin((PetscObject)pc);
    146:   if (!((PetscObject)pc)->type_name) {
    147:     PCGetDefaultType_Private(pc,&def);
    148:   } else {
    149:     def = ((PetscObject)pc)->type_name;
    150:   }

    152:   PetscOptionsFList("-pc_type","Preconditioner","PCSetType",PCList,def,type,256,&flg);
    153:   if (flg) {
    154:     PCSetType(pc,type);
    155:   } else if (!((PetscObject)pc)->type_name) {
    156:     PCSetType(pc,def);
    157:   }

    159:   PetscObjectTypeCompare((PetscObject)pc,PCNONE,&flg);
    160:   if (flg) goto skipoptions;

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

    164:   if (pc->ops->setfromoptions) {
    165:     (*pc->ops->setfromoptions)(PetscOptionsObject,pc);
    166:   }

    168:   skipoptions:
    169:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
    170:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)pc);
    171:   PetscOptionsEnd();
    172:   pc->setfromoptionscalled++;
    173:   return(0);
    174: }

    176: /*@
    177:    PCSetDM - Sets the DM that may be used by some preconditioners

    179:    Logically Collective on PC

    181:    Input Parameters:
    182: +  pc - the preconditioner context
    183: -  dm - the dm, can be NULL

    185:    Level: intermediate

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

    191: .seealso: PCGetDM(), KSPSetDM(), KSPGetDM()
    192: @*/
    193: PetscErrorCode  PCSetDM(PC pc,DM dm)
    194: {

    199:   if (dm) {PetscObjectReference((PetscObject)dm);}
    200:   DMDestroy(&pc->dm);
    201:   pc->dm = dm;
    202:   return(0);
    203: }

    205: /*@
    206:    PCGetDM - Gets the DM that may be used by some preconditioners

    208:    Not Collective

    210:    Input Parameter:
    211: . pc - the preconditioner context

    213:    Output Parameter:
    214: .  dm - the dm

    216:    Level: intermediate

    218: .seealso: PCSetDM(), KSPSetDM(), KSPGetDM()
    219: @*/
    220: PetscErrorCode  PCGetDM(PC pc,DM *dm)
    221: {
    224:   *dm = pc->dm;
    225:   return(0);
    226: }

    228: /*@
    229:    PCSetApplicationContext - Sets the optional user-defined context for the linear solver.

    231:    Logically Collective on PC

    233:    Input Parameters:
    234: +  pc - the PC context
    235: -  usrP - optional user context

    237:    Level: intermediate

    239: .seealso: PCGetApplicationContext()
    240: @*/
    241: PetscErrorCode  PCSetApplicationContext(PC pc,void *usrP)
    242: {
    245:   pc->user = usrP;
    246:   return(0);
    247: }

    249: /*@
    250:    PCGetApplicationContext - Gets the user-defined context for the linear solver.

    252:    Not Collective

    254:    Input Parameter:
    255: .  pc - PC context

    257:    Output Parameter:
    258: .  usrP - user context

    260:    Level: intermediate

    262: .seealso: PCSetApplicationContext()
    263: @*/
    264: PetscErrorCode  PCGetApplicationContext(PC pc,void *usrP)
    265: {
    268:   *(void**)usrP = pc->user;
    269:   return(0);
    270: }