Actual source code: ex1.c
petsc-3.5.4 2015-05-23
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,nleaves;
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: PetscOptionsEnd();
96: nroots = 2 + (PetscInt)(rank == 0);
97: nleaves = 2 + (PetscInt)(rank > 0);
98: PetscMalloc1(nleaves,&remote);
99: /* Left periodic neighbor */
100: remote[0].rank = (rank+size-1)%size;
101: remote[0].index = 1;
102: /* Right periodic neighbor */
103: remote[1].rank = (rank+1)%size;
104: remote[1].index = 0;
105: if (rank > 0) { /* All processes reference rank 0, index 1 */
106: remote[2].rank = 0;
107: remote[2].index = 2;
108: }
110: /* Create a star forest for communication. In this example, the leaf space is dense, so we pass NULL. */
111: PetscSFCreate(PETSC_COMM_WORLD,&sf);
112: PetscSFSetFromOptions(sf);
113: PetscSFSetGraph(sf,nroots,nleaves,NULL,PETSC_COPY_VALUES,remote,PETSC_OWN_POINTER);
115: /* View graph, mostly useful for debugging purposes. */
116: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
117: PetscSFView(sf,PETSC_VIEWER_STDOUT_WORLD);
118: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
121: if (test_bcast) { /* broadcast rootdata into leafdata */
122: PetscInt *rootdata,*leafdata;
123: /* Allocate space for send and recieve buffers. This example communicates PetscInt, but other types, including
124: * user-defined structures, could also be used. */
125: PetscMalloc2(nroots,&rootdata,nleaves,&leafdata);
126: /* Set rootdata buffer to be broadcast */
127: for (i=0; i<nroots; i++) rootdata[i] = 100*(rank+1) + i;
128: /* Initialize local buffer, these values are never used. */
129: for (i=0; i<nleaves; i++) leafdata[i] = -1;
130: /* Broadcast entries from rootdata to leafdata. Computation or other communication can be performed between the begin and end calls. */
131: PetscSFBcastBegin(sf,MPIU_INT,rootdata,leafdata);
132: PetscSFBcastEnd(sf,MPIU_INT,rootdata,leafdata);
133: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Bcast Rootdata\n");
134: PetscIntView(nroots,rootdata,PETSC_VIEWER_STDOUT_WORLD);
135: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Bcast Leafdata\n");
136: PetscIntView(nleaves,leafdata,PETSC_VIEWER_STDOUT_WORLD);
137: PetscFree2(rootdata,leafdata);
138: }
140: if (test_reduce) { /* Reduce leafdata into rootdata */
141: PetscInt *rootdata,*leafdata;
142: PetscMalloc2(nroots,&rootdata,nleaves,&leafdata);
143: /* Initialize rootdata buffer in which the result of the reduction will appear. */
144: for (i=0; i<nroots; i++) rootdata[i] = 100*(rank+1) + i;
145: /* Set leaf values to reduce. */
146: for (i=0; i<nleaves; i++) leafdata[i] = 1000*(rank+1) + 10*i;
147: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Pre-Reduce Rootdata\n");
148: PetscIntView(nroots,rootdata,PETSC_VIEWER_STDOUT_WORLD);
149: /* Perform reduction. Computation or other communication can be performed between the begin and end calls.
150: * This example sums the values, but other MPI_Ops can be used (e.g MPI_MAX, MPI_PROD). */
151: PetscSFReduceBegin(sf,MPIU_INT,leafdata,rootdata,mop);
152: PetscSFReduceEnd(sf,MPIU_INT,leafdata,rootdata,mop);
153: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Reduce Leafdata\n");
154: PetscIntView(nleaves,leafdata,PETSC_VIEWER_STDOUT_WORLD);
155: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Reduce Rootdata\n");
156: PetscIntView(nroots,rootdata,PETSC_VIEWER_STDOUT_WORLD);
157: PetscFree2(rootdata,leafdata);
158: }
160: if (test_degree) {
161: const PetscInt *degree;
162: PetscSFComputeDegreeBegin(sf,°ree);
163: PetscSFComputeDegreeEnd(sf,°ree);
164: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Root degrees\n");
165: PetscIntView(nroots,degree,PETSC_VIEWER_STDOUT_WORLD);
166: }
168: if (test_fetchandop) {
169: /* Cannot use text compare here because token ordering is not deterministic */
170: PetscInt *leafdata,*leafupdate,*rootdata;
171: PetscMalloc3(nleaves,&leafdata,nleaves,&leafupdate,nroots,&rootdata);
172: for (i=0; i<nleaves; i++) leafdata[i] = 1;
173: for (i=0; i<nroots; i++) rootdata[i] = 0;
174: PetscSFFetchAndOpBegin(sf,MPIU_INT,rootdata,leafdata,leafupdate,mop);
175: PetscSFFetchAndOpEnd(sf,MPIU_INT,rootdata,leafdata,leafupdate,mop);
176: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Rootdata (sum of 1 from each leaf)\n");
177: PetscIntView(nroots,rootdata,PETSC_VIEWER_STDOUT_WORLD);
178: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Leafupdate (value at roots prior to my atomic update)\n");
179: PetscIntView(nleaves,leafupdate,PETSC_VIEWER_STDOUT_WORLD);
180: PetscFree3(leafdata,leafupdate,rootdata);
181: }
183: if (test_gather) {
184: const PetscInt *degree;
185: PetscInt inedges,*indata,*outdata;
186: PetscSFComputeDegreeBegin(sf,°ree);
187: PetscSFComputeDegreeEnd(sf,°ree);
188: for (i=0,inedges=0; i<nroots; i++) inedges += degree[i];
189: PetscMalloc2(inedges,&indata,nleaves,&outdata);
190: for (i=0; i<nleaves; i++) outdata[i] = 1000*(rank+1) + i;
191: PetscSFGatherBegin(sf,MPIU_INT,outdata,indata);
192: PetscSFGatherEnd(sf,MPIU_INT,outdata,indata);
193: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Gathered data at multi-roots from leaves\n");
194: PetscIntView(inedges,indata,PETSC_VIEWER_STDOUT_WORLD);
195: PetscFree2(indata,outdata);
196: }
198: if (test_scatter) {
199: const PetscInt *degree;
200: PetscInt j,count,inedges,*indata,*outdata;
201: PetscSFComputeDegreeBegin(sf,°ree);
202: PetscSFComputeDegreeEnd(sf,°ree);
203: for (i=0,inedges=0; i<nroots; i++) inedges += degree[i];
204: PetscMalloc2(inedges,&indata,nleaves,&outdata);
205: for (i=0,count=0; i<nroots; i++) {
206: for (j=0; j<degree[i]; j++) indata[count++] = 1000*(rank+1) + 100*i + j;
207: }
208: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Data at multi-roots, to scatter to leaves\n");
209: PetscIntView(inedges,indata,PETSC_VIEWER_STDOUT_WORLD);
211: PetscSFScatterBegin(sf,MPIU_INT,indata,outdata);
212: PetscSFScatterEnd(sf,MPIU_INT,indata,outdata);
213: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Scattered data at leaves\n");
214: PetscIntView(nleaves,outdata,PETSC_VIEWER_STDOUT_WORLD);
215: PetscFree2(indata,outdata);
216: }
218: if (test_embed) {
219: const PetscInt nroots = 1 + (PetscInt) !rank,selected[] = {1,2};
220: PetscSF esf;
221: PetscSFCreateEmbeddedSF(sf,nroots,selected,&esf);
222: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Embedded PetscSF\n");
223: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
224: PetscSFView(esf,PETSC_VIEWER_STDOUT_WORLD);
225: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
226: PetscSFDestroy(&esf);
227: }
229: if (test_invert) {
230: PetscSF msf,imsf;
231: PetscSFGetMultiSF(sf,&msf);
232: PetscSFCreateInverseSF(msf,&imsf);
233: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Multi-SF\n");
234: PetscSFView(msf,PETSC_VIEWER_STDOUT_WORLD);
235: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_WORLD,"## Inverse of Multi-SF\n");
236: PetscSFView(imsf,PETSC_VIEWER_STDOUT_WORLD);
237: PetscSFDestroy(&imsf);
238: }
240: /* Clean storage for star forest. */
241: PetscSFDestroy(&sf);
242: PetscFinalize();
243: return 0;
244: }