1: #define PETSCKSP_DLL
  2: /*
  3:     Routines to set PC methods and options.
  4: */

 6:  #include private/pcimpl.h
 7:  #include petscsys.h

  9: PetscTruth PCRegisterAllCalled = PETSC_FALSE;
 10: /*
 11:    Contains the list of registered KSP routines
 12: */
 13: PetscFList PCList = 0;

 17: /*@C
 18:    PCSetType - Builds PC for a particular preconditioner.

 20:    Collective on PC

 22:    Input Parameter:
 23: +  pc - the preconditioner context.
 24: -  type - a known method

 26:    Options Database Key:
 27: .  -pc_type <type> - Sets PC type

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

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

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

 48:   Level: intermediate

 50: .keywords: PC, set, method, type

 52: .seealso: KSPSetType(), PCType

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


 64:   PetscTypeCompare((PetscObject)pc,type,&match);
 65:   if (match) return(0);

 67:   if (pc->ops->destroy) { (*pc->ops->destroy)(pc);}
 68:   PetscFListDestroy(&pc->qlist);
 69:   pc->data        = 0;
 70:   pc->setupcalled = 0;

 72:   /* Get the function pointers for the method requested */
 73:   if (!PCRegisterAllCalled) {PCRegisterAll(0);}

 75:   /* Determine the PCCreateXXX routine for a particular preconditioner */
 76:    PetscFListFind(pc->comm,PCList,type,(void (**)(void)) &r);
 77:   if (!r) SETERRQ1(PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested PC type %s",type);
 78:   PetscFree(pc->data);

 80:   pc->ops->setup               = (PetscErrorCode (*)(PC)) 0;
 81:   pc->ops->apply               = (PetscErrorCode (*)(PC,Vec,Vec)) 0;
 82:   pc->ops->applyrichardson     = (PetscErrorCode (*)(PC,Vec,Vec,Vec,PetscReal,PetscReal,PetscReal,PetscInt)) 0;
 83:   pc->ops->applyBA             = (PetscErrorCode (*)(PC,PCSide,Vec,Vec,Vec)) 0;
 84:   pc->ops->applytranspose      = (PetscErrorCode (*)(PC,Vec,Vec)) 0;
 85:   pc->ops->applyBAtranspose    = (PetscErrorCode (*)(PC,PetscInt,Vec,Vec,Vec)) 0;
 86:   pc->ops->setfromoptions      = (PetscErrorCode (*)(PC)) 0;
 87:   pc->ops->presolve            = (PetscErrorCode (*)(PC,KSP,Vec,Vec)) 0;
 88:   pc->ops->postsolve           = (PetscErrorCode (*)(PC,KSP,Vec,Vec)) 0;
 89:   pc->ops->getfactoredmatrix   = (PetscErrorCode (*)(PC,Mat*)) 0;
 90:   pc->ops->applysymmetricleft  = (PetscErrorCode (*)(PC,Vec,Vec)) 0;
 91:   pc->ops->applysymmetricright = (PetscErrorCode (*)(PC,Vec,Vec)) 0;
 92:   pc->ops->setuponblocks       = (PetscErrorCode (*)(PC)) 0;
 93:   pc->ops->destroy             = (PetscErrorCode (*)(PC)) 0;
 94:   pc->ops->view                = (PetscErrorCode (*)(PC,PetscViewer)) 0;
 95:   pc->modifysubmatrices        = (PetscErrorCode (*)(PC,PetscInt,const IS[],const IS[],Mat[],void*)) 0;

 97:   /* Call the PCCreateXXX routine for this particular preconditioner */
 98:   (*r)(pc);

100:   PetscObjectChangeTypeName((PetscObject)pc,type);
101:   return(0);
102: }

106: /*@
107:    PCRegisterDestroy - Frees the list of preconditioners that were
108:    registered by PCRegisterDynamic().

110:    Not Collective

112:    Level: advanced

114: .keywords: PC, register, destroy

116: .seealso: PCRegisterAll(), PCRegisterAll()

118: @*/
119: PetscErrorCode  PCRegisterDestroy(void)
120: {

124:   if (PCList) {
125:     PetscFListDestroy(&PCList);
126:     PCList = 0;
127:   }
128:   PCRegisterAllCalled = PETSC_FALSE;
129:   return(0);
130: }

134: /*@C
135:    PCGetType - Gets the PC method type and name (as a string) from the PC
136:    context.

138:    Not Collective

140:    Input Parameter:
141: .  pc - the preconditioner context

143:    Output Parameter:
144: .  name - name of preconditioner 

146:    Level: intermediate

148: .keywords: PC, get, method, name, type

150: .seealso: PCSetType()

152: @*/
153: PetscErrorCode  PCGetType(PC pc,PCType *meth)
154: {
156:   *meth = (PCType) pc->type_name;
157:   return(0);
158: }

160: EXTERN PetscErrorCode PCGetDefaultType_Private(PC,const char*[]);

164: /*@
165:    PCSetFromOptions - Sets PC options from the options database.
166:    This routine must be called before PCSetUp() if the user is to be
167:    allowed to set the preconditioner method. 

169:    Collective on PC

171:    Input Parameter:
172: .  pc - the preconditioner context

174:    Level: developer

176: .keywords: PC, set, from, options, database

178: .seealso: 

180: @*/
181: PetscErrorCode  PCSetFromOptions(PC pc)
182: {
184:   char           type[256];
185:   const char     *def;
186:   PetscTruth     flg;


191:   if (!PCRegisterAllCalled) {PCRegisterAll(PETSC_NULL);}
192:   PetscOptionsBegin(pc->comm,pc->prefix,"Preconditioner (PC) Options","PC");
193:     if (!pc->type_name) {
194:       PCGetDefaultType_Private(pc,&def);
195:     } else {
196:       def = pc->type_name;
197:     }

199:     PetscOptionsList("-pc_type","Preconditioner","PCSetType",PCList,def,type,256,&flg);
200:     if (flg) {
201:       PCSetType(pc,type);
202:     } else if (!pc->type_name){
203:       PCSetType(pc,def);
204:     }

206:     if (pc->ops->setfromoptions) {
207:       (*pc->ops->setfromoptions)(pc);
208:     }
209:   PetscOptionsEnd();
210:   return(0);
211: }