Actual source code: pcset.c

petsc-master 2019-06-22
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  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 KSP routines
 12: */
 13: PetscFunctionList PCList = 0;

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

 18:    Collective on PC

 20:    Input Parameter:
 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         = 0;
 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  = 0;
 79:   pc->modifysubmatricesP = 0;
 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


219: .seealso: PCSetDM(), KSPSetDM(), KSPGetDM()
220: @*/
221: PetscErrorCode  PCGetDM(PC pc,DM *dm)
222: {
225:   *dm = pc->dm;
226:   return(0);
227: }

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

232:    Logically Collective on PC

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

238:    Level: intermediate

240: .seealso: PCGetApplicationContext()
241: @*/
242: PetscErrorCode  PCSetApplicationContext(PC pc,void *usrP)
243: {
246:   pc->user = usrP;
247:   return(0);
248: }

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

253:    Not Collective

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

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

261:    Level: intermediate

263: .seealso: PCSetApplicationContext()
264: @*/
265: PetscErrorCode  PCGetApplicationContext(PC pc,void *usrP)
266: {
269:   *(void**)usrP = pc->user;
270:   return(0);
271: }