Actual source code: tagm.c

  1: /*$Id: tagm.c,v 1.33 2001/03/23 23:20:38 balay Exp $*/
  2: /*
  3:       Some PETSc utilites
  4: */
 5:  #include petscsys.h
  6: #if defined(PETSC_HAVE_STDLIB_H)
  7: #include <stdlib.h>
  8: #endif

 10: /* ---------------------------------------------------------------- */
 11: /*
 12:    A simple way to manage tags inside a private 
 13:    communicator.  It uses the attribute to determine if a new communicator
 14:    is needed.

 16:    Notes on the implementation

 18:    The tagvalues to use are stored in a two element array.  The first element
 19:    is the first free tag value.  The second is used to indicate how
 20:    many "copies" of the communicator there are used in destroying.
 21: */

 23: static int Petsc_Tag_keyval = MPI_KEYVAL_INVALID;

 25: EXTERN_C_BEGIN
 28: /*
 29:    Private routine to delete internal storage when a communicator is freed.
 30:   This is called by MPI, not by users.

 32:   The binding for the first argument changed from MPI 1.0 to 1.1; in 1.0
 33:   it was MPI_Comm *comm.  

 35:     Note: this is declared extern "C" because it is passed to the system routine signal()
 36:           which is an extern "C" routine. The Solaris 2.7 OS compilers require that this be
 37:           extern "C".
 38: */
 39: int Petsc_DelTag(MPI_Comm comm,int keyval,void* attr_val,void* extra_state)
 40: {

 44:   PetscLogInfo(0,"Petsc_DelTag:Deleting tag data in an MPI_Comm %ld\n",(long)comm);
 45:   PetscFree(attr_val);
 46:   PetscFunctionReturn(MPI_SUCCESS);
 47: }
 48: EXTERN_C_END

 52: /*@C
 53:     PetscObjectGetNewTag - Gets a unique new tag from a PETSc object. All 
 54:     processors that share the object MUST call this routine EXACTLY the same
 55:     number of times.  This tag should only be used with the current objects
 56:     communicator; do NOT use it with any other MPI communicator.

 58:     Collective on PetscObject

 60:     Input Parameter:
 61: .   obj - the PETSc object; this must be cast with a (PetscObject), for example, 
 62:          PetscObjectGetNewTag((PetscObject)mat,&tag);

 64:     Output Parameter:
 65: .   tag - the new tag

 67:     Level: developer

 69:     Concepts: tag^getting
 70:     Concepts: message tag^getting
 71:     Concepts: MPI message tag^getting

 73: .seealso: PetscCommGetNewTag()
 74: @*/
 75: int PetscObjectGetNewTag(PetscObject obj,int *tag)
 76: {
 77:   int        ierr,*tagvalp=0,*maxval;
 78:   PetscTruth flg;


 84:   MPI_Attr_get(obj->comm,Petsc_Tag_keyval,(void**)&tagvalp,(int*)&flg);
 85:   if (!flg) SETERRQ(PETSC_ERR_ARG_CORRUPT,"Bad MPI communicator in PETSc object, likely memory corruption");

 87:   if (tagvalp[0] < 1) {
 88:     PetscLogInfo(0,"Out of tags for object, starting to recycle. Number tags issued %d",tagvalp[1]);
 89:     MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,(void**)&maxval,(int*)&flg);
 90:     if (!flg) {
 91:       SETERRQ(1,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB");
 92:     }
 93:     tagvalp[0] = *maxval - 128; /* hope that any still active tags were issued right at the beginning of the run */
 94:   }

 96:   *tag = tagvalp[0]--;
 97:   return(0);
 98: }

102: /*@C
103:     PetscCommGetNewTag - Gets a unique new tag from a PETSc communicator. All 
104:     processors that share the communicator MUST call this routine EXACTLY the same
105:     number of times.  This tag should only be used with the current objects
106:     communicator; do NOT use it with any other MPI communicator.

108:     Collective on comm

110:     Input Parameter:
111: .   comm - the PETSc communicator

113:     Output Parameter:
114: .   tag - the new tag

116:     Level: developer

118:     Concepts: tag^getting
119:     Concepts: message tag^getting
120:     Concepts: MPI message tag^getting

122: .seealso: PetscObjectGetNewTag(), PetscCommDuplicate()
123: @*/
124: int PetscCommGetNewTag(MPI_Comm comm,int *tag)
125: {
126:   int        ierr,*tagvalp=0,*maxval;
127:   PetscTruth flg;


132:   MPI_Attr_get(comm,Petsc_Tag_keyval,(void**)&tagvalp,(int*)&flg);
133:   if (!flg) SETERRQ(PETSC_ERR_ARG_CORRUPT,"Bad MPI communicator supplied; must be a PETSc communicator");


136:   if (tagvalp[0] < 1) {
137:     PetscLogInfo(0,"Out of tags for object, starting to recycle. Number tags issued %d",tagvalp[1]);
138:     MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,(void**)&maxval,(int*)&flg);
139:     if (!flg) {
140:       SETERRQ(1,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB");
141:     }
142:     tagvalp[0] = *maxval - 128; /* hope that any still active tags were issued right at the beginning of the run */
143:   }

145:   *tag = tagvalp[0]--;
146:   return(0);
147: }

151: /*@C
152:   PetscCommDuplicate - Duplicates the communicator only if it is not already a PETSc 
153:                          communicator.

155:   Collective on MPI_Comm

157:   Input Parameters:
158: . comm_in - Input communicator

160:   Output Parameters:
161: + comm_out - Output communicator.  May be comm_in.
162: - first_tag - Tag available that has not already been used with this communicator (you may
163:               pass in PETSC_NULL if you do not need a tag)

165:   PETSc communicators are just regular MPI communicators that keep track of which 
166:   tags have been used to prevent tag conflict. If you pass a non-PETSc communicator into
167:   a PETSc creation routine it will be duplicated for use in the object.

169:   Level: developer

171:   Concepts: communicator^duplicate

173: .seealso: PetscObjectGetNewTag(), PetscCommGetNewTag()
174: @*/
175: int PetscCommDuplicate(MPI_Comm comm_in,MPI_Comm *comm_out,int* first_tag)
176: {
177:   int        ierr,*tagvalp,*maxval;
178:   PetscTruth flg;

181:   if (Petsc_Tag_keyval == MPI_KEYVAL_INVALID) {
182:     /* 
183:        The calling sequence of the 2nd argument to this function changed
184:        between MPI Standard 1.0 and the revisions 1.1 Here we match the 
185:        new standard, if you are using an MPI implementation that uses 
186:        the older version you will get a warning message about the next line;
187:        it is only a warning message and should do no harm.
188:     */
189:     MPI_Keyval_create(MPI_NULL_COPY_FN,Petsc_DelTag,&Petsc_Tag_keyval,(void*)0);
190:   }

192:   MPI_Attr_get(comm_in,Petsc_Tag_keyval,(void**)&tagvalp,(int*)&flg);

194:   if (!flg) {
195:     /* This communicator is not yet known to this system, so we duplicate it and set its value */
196:     MPI_Comm_dup(comm_in,comm_out);
197:     MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,(void**)&maxval,(int*)&flg);
198:     if (!flg) {
199:       SETERRQ(1,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB");
200:     }
201:     PetscMalloc(2*sizeof(int),&tagvalp);
202:     tagvalp[0] = *maxval;
203:     tagvalp[1] = 0;
204:     MPI_Attr_put(*comm_out,Petsc_Tag_keyval,tagvalp);
205:     PetscLogInfo(0,"PetscCommDuplicate: Duplicating a communicator %ld %ld max tags = %d\n",(long)comm_in,(long)*comm_out,*maxval);
206:   } else {
207: #if defined(PETSC_USE_BOPT_g)
208:     int tag;
209:     MPI_Allreduce(tagvalp,&tag,1,MPI_INT,MPI_BOR,comm_in);
210:     if (tag != tagvalp[0]) {
211:       SETERRQ(PETSC_ERR_ARG_CORRUPT,"Communicator was used on subset of processors.");
212:     }
213: #endif
214:     *comm_out = comm_in;
215:   }

217:   if (tagvalp[0] < 1) {
218:     PetscLogInfo(0,"Out of tags for object, starting to recycle. Number tags issued %d",tagvalp[1]);
219:     MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,(void**)&maxval,(int*)&flg);
220:     if (!flg) {
221:       SETERRQ(1,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB");
222:     }
223:     tagvalp[0] = *maxval - 128; /* hope that any still active tags were issued right at the beginning of the run */
224:   }

226:   if (first_tag) {
227:     *first_tag = tagvalp[0]--;
228:     tagvalp[1]++;
229:   }
230:   return(0);
231: }

235: /*@C
236:    PetscCommDestroy - Frees communicator.  Use in conjunction with PetscCommDuplicate().

238:    Collective on MPI_Comm

240:    Input Parameter:
241: .  comm - the communicator to free

243:    Level: developer

245:    Concepts: communicator^destroy

247: @*/
248: int PetscCommDestroy(MPI_Comm *comm)
249: {
250:   int        ierr,*tagvalp;
251:   PetscTruth flg;

254:   MPI_Attr_get(*comm,Petsc_Tag_keyval,(void**)&tagvalp,(int*)&flg);
255:   if (!flg) {
256:     SETERRQ(PETSC_ERR_ARG_CORRUPT,"Error freeing MPI_Comm, problem with corrupted memory");
257:   }
258:   tagvalp[1]--;
259:   if (!tagvalp[1]) {
260:     PetscLogInfo(0,"PetscCommDestroy:Deleting MPI_Comm %ld\n",(long)*comm);
261:     MPI_Comm_free(comm);
262:   }
263:   return(0);
264: }