Actual source code: ex1.c

petsc-3.7.3 2016-07-24
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  1: static const char help[] = "Test star forest communication (PetscSF)\n\n";

  3: /*T
  4:     Description: A star forest is a simple tree with one root and zero or more leaves.
  5:     Many common communication patterns can be expressed as updates of rootdata using leafdata and vice-versa.
  6:     This example creates a star forest, communicates values using the graph (see options for types of communication), views the graph, then destroys it.
  7: T*/

  9: /*
 10:   Include petscsf.h so we can use PetscSF objects. Note that this automatically
 11:   includes petscsys.h.
 12: */
 13: #include <petscsf.h>
 14: #include <petscviewer.h>

 18: int main(int argc,char **argv)
 19: {
 21:   PetscInt       i,nroots,nrootsalloc,nleaves,nleavesalloc,*mine,stride;
 22:   PetscSFNode    *remote;
 23:   PetscMPIInt    rank,size;
 24:   PetscSF        sf;
 25:   PetscBool      test_bcast,test_reduce,test_degree,test_fetchandop,test_gather,test_scatter,test_embed,test_invert;
 26:   MPI_Op         mop;
 27:   char           opstring[256];
 28:   PetscBool      strflg;

 30:   PetscInitialize(&argc,&argv,(char*)0,help);
 31:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 32:   MPI_Comm_size(PETSC_COMM_WORLD,&size);

 34:   PetscOptionsBegin(PETSC_COMM_WORLD,"","PetscSF Test Options","none");
 35:   test_bcast      = PETSC_FALSE;
 36:   PetscOptionsBool("-test_bcast","Test broadcast","",test_bcast,&test_bcast,NULL);
 37:   test_reduce     = PETSC_FALSE;
 38:   PetscOptionsBool("-test_reduce","Test reduction","",test_reduce,&test_reduce,NULL);
 39:   mop             = MPI_SUM;
 40:   PetscStrcpy(opstring,"sum");
 41:   PetscOptionsString("-test_op","Designate which MPI_Op to use","",opstring,opstring,256,NULL);
 42:   PetscStrcmp("sum",opstring,&strflg);
 43:   if (strflg) {
 44:     mop = MPIU_SUM;
 45:   }
 46:   PetscStrcmp("prod",opstring,&strflg);
 47:   if (strflg) {
 48:     mop = MPI_PROD;
 49:   }
 50:   PetscStrcmp("max",opstring,&strflg);
 51:   if (strflg) {
 52:     mop = MPI_MAX;
 53:   }
 54:   PetscStrcmp("min",opstring,&strflg);
 55:   if (strflg) {
 56:     mop = MPI_MIN;
 57:   }
 58:   PetscStrcmp("land",opstring,&strflg);
 59:   if (strflg) {
 60:     mop = MPI_LAND;
 61:   }
 62:   PetscStrcmp("band",opstring,&strflg);
 63:   if (strflg) {
 64:     mop = MPI_BAND;
 65:   }
 66:   PetscStrcmp("lor",opstring,&strflg);
 67:   if (strflg) {
 68:     mop = MPI_LOR;
 69:   }
 70:   PetscStrcmp("bor",opstring,&strflg);
 71:   if (strflg) {
 72:     mop = MPI_BOR;
 73:   }
 74:   PetscStrcmp("lxor",opstring,&strflg);
 75:   if (strflg) {
 76:     mop = MPI_LXOR;
 77:   }
 78:   PetscStrcmp("bxor",opstring,&strflg);
 79:   if (strflg) {
 80:     mop = MPI_BXOR;
 81:   }
 82:   test_degree     = PETSC_FALSE;
 83:   PetscOptionsBool("-test_degree","Test computation of vertex degree","",test_degree,&test_degree,NULL);
 84:   test_fetchandop = PETSC_FALSE;
 85:   PetscOptionsBool("-test_fetchandop","Test atomic Fetch-And-Op","",test_fetchandop,&test_fetchandop,NULL);
 86:   test_gather     = PETSC_FALSE;
 87:   PetscOptionsBool("-test_gather","Test point gather","",test_gather,&test_gather,NULL);
 88:   test_scatter    = PETSC_FALSE;
 89:   PetscOptionsBool("-test_scatter","Test point scatter","",test_scatter,&test_scatter,NULL);
 90:   test_embed      = PETSC_FALSE;
 91:   PetscOptionsBool("-test_embed","Test point embed","",test_embed,&test_embed,NULL);
 92:   test_invert     = PETSC_FALSE;
 93:   PetscOptionsBool("-test_invert","Test point invert","",test_invert,&test_invert,NULL);
 94:   stride          = 1;
 95:   PetscOptionsInt("-stride","Stride for leaf and root data","",stride,&stride,NULL);
 96:   PetscOptionsEnd();

 98:   nroots       = 2 + (PetscInt)(rank == 0);
 99:   nrootsalloc  = nroots * stride;
100:   nleaves      = 2 + (PetscInt)(rank > 0);
101:   nleavesalloc = nleaves * stride;
102:   mine         = NULL;
103:   if (stride > 1) {
104:     PetscInt i;

106:     PetscMalloc1(nleaves,&mine);
107:     for (i = 0; i < nleaves; i++) {
108:       mine[i] = stride * i;
109:     }
110:   }
111:   PetscMalloc1(nleaves,&remote);
112:   /* Left periodic neighbor */
113:   remote[0].rank  = (rank+size-1)%size;
114:   remote[0].index = 1 * stride;
115:   /* Right periodic neighbor */
116:   remote[1].rank  = (rank+1)%size;
117:   remote[1].index = 0 * stride;
118:   if (rank > 0) {               /* All processes reference rank 0, index 1 */
119:     remote[2].rank  = 0;
120:     remote[2].index = 2 * stride;
121:   }

123:   /* Create a star forest for communication. In this example, the leaf space is dense, so we pass NULL. */
124:   PetscSFCreate(PETSC_COMM_WORLD,&sf);
125:   PetscSFSetFromOptions(sf);
126:   PetscSFSetGraph(sf,nrootsalloc,nleaves,mine,PETSC_OWN_POINTER,remote,PETSC_OWN_POINTER);

128:   /* View graph, mostly useful for debugging purposes. */
129:   PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
130:   PetscSFView(sf,PETSC_VIEWER_STDOUT_WORLD);
131:   PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);


134:   if (test_bcast) {             /* broadcast rootdata into leafdata */
135:     PetscInt *rootdata,*leafdata;
136:     /* Allocate space for send and recieve buffers. This example communicates PetscInt, but other types, including
137:      * user-defined structures, could also be used. */
138:     PetscMalloc2(nrootsalloc,&rootdata,nleavesalloc,&leafdata);
139:     /* Set rootdata buffer to be broadcast */
140:     for (i=0; i<nrootsalloc; i++) rootdata[i] = -1;
141:     for (i=0; i<nroots; i++) rootdata[i*stride] = 100*(rank+1) + i;
142:     /* Initialize local buffer, these values are never used. */
143:     for (i=0; i<nleavesalloc; i++) leafdata[i] = -1;
144:     /* Broadcast entries from rootdata to leafdata. Computation or other communication can be performed between the begin and end calls. */
145:     PetscSFBcastBegin(sf,MPIU_INT,rootdata,leafdata);
146:     PetscSFBcastEnd(sf,MPIU_INT,rootdata,leafdata);
147:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Bcast Rootdata\n");
148:     PetscIntView(nrootsalloc,rootdata,PETSC_VIEWER_STDOUT_WORLD);
149:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Bcast Leafdata\n");
150:     PetscIntView(nleavesalloc,leafdata,PETSC_VIEWER_STDOUT_WORLD);
151:     PetscFree2(rootdata,leafdata);
152:   }

154:   if (test_reduce) {            /* Reduce leafdata into rootdata */
155:     PetscInt *rootdata,*leafdata;
156:     PetscMalloc2(nrootsalloc,&rootdata,nleavesalloc,&leafdata);
157:     /* Initialize rootdata buffer in which the result of the reduction will appear. */
158:     for (i=0; i<nrootsalloc; i++) rootdata[i] = -1;
159:     for (i=0; i<nroots; i++) rootdata[i*stride] = 100*(rank+1) + i;
160:     /* Set leaf values to reduce. */
161:     for (i=0; i<nleavesalloc; i++) leafdata[i] = -1;
162:     for (i=0; i<nleaves; i++) leafdata[i*stride] = 1000*(rank+1) + 10*i;
163:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Pre-Reduce Rootdata\n");
164:     PetscIntView(nrootsalloc,rootdata,PETSC_VIEWER_STDOUT_WORLD);
165:     /* Perform reduction. Computation or other communication can be performed between the begin and end calls.
166:      * This example sums the values, but other MPI_Ops can be used (e.g MPI_MAX, MPI_PROD). */
167:     PetscSFReduceBegin(sf,MPIU_INT,leafdata,rootdata,mop);
168:     PetscSFReduceEnd(sf,MPIU_INT,leafdata,rootdata,mop);
169:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Reduce Leafdata\n");
170:     PetscIntView(nleavesalloc,leafdata,PETSC_VIEWER_STDOUT_WORLD);
171:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Reduce Rootdata\n");
172:     PetscIntView(nrootsalloc,rootdata,PETSC_VIEWER_STDOUT_WORLD);
173:     PetscFree2(rootdata,leafdata);
174:   }

176:   if (test_degree) {
177:     const PetscInt *degree;
178:     PetscSFComputeDegreeBegin(sf,&degree);
179:     PetscSFComputeDegreeEnd(sf,&degree);
180:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Root degrees\n");
181:     PetscIntView(nrootsalloc,degree,PETSC_VIEWER_STDOUT_WORLD);
182:   }

184:   if (test_fetchandop) {
185:     /* Cannot use text compare here because token ordering is not deterministic */
186:     PetscInt *leafdata,*leafupdate,*rootdata;
187:     PetscMalloc3(nleavesalloc,&leafdata,nleavesalloc,&leafupdate,nrootsalloc,&rootdata);
188:     for (i=0; i<nleavesalloc; i++) leafdata[i] = -1;
189:     for (i=0; i<nleaves; i++) leafdata[i*stride] = 1;
190:     for (i=0; i<nrootsalloc; i++) rootdata[i] = -1;
191:     for (i=0; i<nroots; i++) rootdata[i*stride] = 0;
192:     PetscSFFetchAndOpBegin(sf,MPIU_INT,rootdata,leafdata,leafupdate,mop);
193:     PetscSFFetchAndOpEnd(sf,MPIU_INT,rootdata,leafdata,leafupdate,mop);
194:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Rootdata (sum of 1 from each leaf)\n");
195:     PetscIntView(nrootsalloc,rootdata,PETSC_VIEWER_STDOUT_WORLD);
196:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Leafupdate (value at roots prior to my atomic update)\n");
197:     PetscIntView(nleavesalloc,leafupdate,PETSC_VIEWER_STDOUT_WORLD);
198:     PetscFree3(leafdata,leafupdate,rootdata);
199:   }

201:   if (test_gather) {
202:     const PetscInt *degree;
203:     PetscInt       inedges,*indata,*outdata;
204:     PetscSFComputeDegreeBegin(sf,&degree);
205:     PetscSFComputeDegreeEnd(sf,&degree);
206:     for (i=0,inedges=0; i<nrootsalloc; i++) inedges += degree[i];
207:     PetscMalloc2(inedges,&indata,nleavesalloc,&outdata);
208:     for (i=0; i<nleavesalloc; i++) outdata[i] = -1;
209:     for (i=0; i<nleaves; i++) outdata[i*stride] = 1000*(rank+1) + i;
210:     PetscSFGatherBegin(sf,MPIU_INT,outdata,indata);
211:     PetscSFGatherEnd(sf,MPIU_INT,outdata,indata);
212:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Gathered data at multi-roots from leaves\n");
213:     PetscIntView(inedges,indata,PETSC_VIEWER_STDOUT_WORLD);
214:     PetscFree2(indata,outdata);
215:   }

217:   if (test_scatter) {
218:     const PetscInt *degree;
219:     PetscInt       j,count,inedges,*indata,*outdata;
220:     PetscSFComputeDegreeBegin(sf,&degree);
221:     PetscSFComputeDegreeEnd(sf,&degree);
222:     for (i=0,inedges=0; i<nrootsalloc; i++) inedges += degree[i];
223:     PetscMalloc2(inedges,&indata,nleavesalloc,&outdata);
224:     for (i=0; i<nleavesalloc; i++) outdata[i] = -1;
225:     for (i=0,count=0; i<nrootsalloc; i++) {
226:       for (j=0; j<degree[i]; j++) indata[count++] = 1000*(rank+1) + 100*i + j;
227:     }
228:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Data at multi-roots, to scatter to leaves\n");
229:     PetscIntView(inedges,indata,PETSC_VIEWER_STDOUT_WORLD);

231:     PetscSFScatterBegin(sf,MPIU_INT,indata,outdata);
232:     PetscSFScatterEnd(sf,MPIU_INT,indata,outdata);
233:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Scattered data at leaves\n");
234:     PetscIntView(nleavesalloc,outdata,PETSC_VIEWER_STDOUT_WORLD);
235:     PetscFree2(indata,outdata);
236:   }

238:   if (test_embed) {
239:     const PetscInt nroots = 1 + (PetscInt) !rank,selected[] = {1*stride,2*stride};
240:     PetscSF        esf;
241:     PetscSFCreateEmbeddedSF(sf,nroots,selected,&esf);
242:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Embedded PetscSF\n");
243:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
244:     PetscSFView(esf,PETSC_VIEWER_STDOUT_WORLD);
245:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
246:     PetscSFDestroy(&esf);
247:   }

249:   if (test_invert) {
250:     PetscSF msf,imsf;
251:     PetscSFGetMultiSF(sf,&msf);
252:     PetscSFCreateInverseSF(msf,&imsf);
253:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Multi-SF\n");
254:     PetscSFView(msf,PETSC_VIEWER_STDOUT_WORLD);
255:     PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Inverse of Multi-SF\n");
256:     PetscSFView(imsf,PETSC_VIEWER_STDOUT_WORLD);
257:     PetscSFDestroy(&imsf);
258:   }

260:   /* Clean storage for star forest. */
261:   PetscSFDestroy(&sf);
262:   PetscFinalize();
263:   return 0;
264: }