xref: /petsc/src/vec/is/sf/tests/ex14.c (revision fbf9dbe564678ed6eff1806adbc4c4f01b9743f4)
1 
2 static char help[] = "Test event log of VecScatter with various block sizes\n\n";
3 
4 #include <petscvec.h>
5 
6 int main(int argc, char **argv)
7 {
8   PetscInt           i, j, low, high, n = 256, N, errors, tot_errors;
9   PetscInt           bs = 1, ix[2], iy[2];
10   PetscMPIInt        nproc, rank;
11   PetscScalar       *xval;
12   const PetscScalar *yval;
13   Vec                x, y;
14   IS                 isx, isy;
15   VecScatter         ctx;
16   const PetscInt     niter = 10;
17 #if defined(PETSC_USE_LOG)
18   PetscLogStage      stage1, stage2;
19   PetscLogEvent      event1, event2;
20   PetscLogDouble     numMessages, messageLength;
21   PetscEventPerfInfo eventInfo;
22   PetscInt           tot_msg, tot_len, avg_len;
23 #endif
24 
25   PetscFunctionBegin;
26   PetscFunctionBeginUser;
27   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
28   PetscCall(PetscLogDefaultBegin());
29   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &nproc));
30   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
31 
32   PetscCall(PetscLogStageRegister("Scatter(bs=1)", &stage1));
33   PetscCall(PetscLogEventRegister("VecScatter(bs=1)", PETSC_OBJECT_CLASSID, &event1));
34   PetscCall(PetscLogStageRegister("Scatter(bs=4)", &stage2));
35   PetscCall(PetscLogEventRegister("VecScatter(bs=4)", PETSC_OBJECT_CLASSID, &event2));
36 
37   /* Create a parallel vector x and a sequential vector y */
38   PetscCall(VecCreate(PETSC_COMM_WORLD, &x));
39   PetscCall(VecSetSizes(x, n, PETSC_DECIDE));
40   PetscCall(VecSetFromOptions(x));
41   PetscCall(VecGetOwnershipRange(x, &low, &high));
42   PetscCall(VecGetSize(x, &N));
43   PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &y));
44 
45   /*=======================================
46      test VecScatter with bs = 1
47     ======================================*/
48 
49   /* the code works as if we are going to do 3-point stencil computations on a 1D domain x,
50      which has periodic boundary conditions but the two ghosts are scatterred to beginning of y.
51    */
52   bs    = 1;
53   ix[0] = rank ? low - 1 : N - 1; /* ix[] contains global indices of the two ghost points */
54   ix[1] = (rank != nproc - 1) ? high : 0;
55   iy[0] = 0;
56   iy[1] = 1;
57 
58   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 2, ix, PETSC_COPY_VALUES, &isx));
59   PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 2, iy, PETSC_COPY_VALUES, &isy));
60   PetscCall(VecScatterCreate(x, isx, y, isy, &ctx));
61   PetscCall(VecScatterSetUp(ctx));
62 
63   PetscCall(PetscLogStagePush(stage1));
64   PetscCall(PetscLogEventBegin(event1, 0, 0, 0, 0));
65   errors = 0;
66   for (i = 0; i < niter; i++) {
67     /* set x = 0+i, 1+i, 2+i, ..., N-1+i */
68     PetscCall(VecGetArray(x, &xval));
69     for (j = 0; j < n; j++) xval[j] = (PetscScalar)(low + j + i);
70     PetscCall(VecRestoreArray(x, &xval));
71     /* scatter the ghosts to y */
72     PetscCall(VecScatterBegin(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
73     PetscCall(VecScatterEnd(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
74     /* check if y has correct values */
75     PetscCall(VecGetArrayRead(y, &yval));
76     if ((PetscInt)PetscRealPart(yval[0]) != ix[0] + i) errors++;
77     if ((PetscInt)PetscRealPart(yval[1]) != ix[1] + i) errors++;
78     PetscCall(VecRestoreArrayRead(y, &yval));
79   }
80   PetscCall(PetscLogEventEnd(event1, 0, 0, 0, 0));
81   PetscCall(PetscLogStagePop());
82 
83   /* check if we found wrong values on any processors */
84   PetscCall(MPIU_Allreduce(&errors, &tot_errors, 1, MPIU_INT, MPI_SUM, PETSC_COMM_WORLD));
85   if (tot_errors) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error: wrong values were scatterred in vecscatter with bs = %" PetscInt_FMT "\n", bs));
86 
87     /* print out event log of VecScatter(bs=1) */
88 #if defined(PETSC_USE_LOG)
89   PetscCall(PetscLogEventGetPerfInfo(stage1, event1, &eventInfo));
90   PetscCall(MPIU_Allreduce(&eventInfo.numMessages, &numMessages, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, PETSC_COMM_WORLD));
91   PetscCall(MPIU_Allreduce(&eventInfo.messageLength, &messageLength, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, PETSC_COMM_WORLD));
92   tot_msg = (PetscInt)numMessages * 0.5; /* two MPI calls (Send & Recv) per message */
93   tot_len = (PetscInt)messageLength * 0.5;
94   avg_len = tot_msg ? (PetscInt)(messageLength / numMessages) : 0;
95   /* when nproc > 2, tot_msg = 2*nproc*niter, tot_len = tot_msg*sizeof(PetscScalar)*bs */
96   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "VecScatter(bs=%" PetscInt_FMT ") has sent out %" PetscInt_FMT " messages, total %" PetscInt_FMT " bytes, with average length %" PetscInt_FMT " bytes\n", bs, tot_msg, tot_len, avg_len));
97 #endif
98 
99   PetscCall(ISDestroy(&isx));
100   PetscCall(ISDestroy(&isy));
101   PetscCall(VecScatterDestroy(&ctx));
102 
103   /*=======================================
104      test VecScatter with bs = 4
105     ======================================*/
106 
107   /* similar to the 3-point stencil above, except that this time a ghost is a block */
108   bs    = 4;                                /* n needs to be a multiple of bs to make the following code work */
109   ix[0] = rank ? low / bs - 1 : N / bs - 1; /* ix[] contains global indices of the two ghost blocks */
110   ix[1] = (rank != nproc - 1) ? high / bs : 0;
111   iy[0] = 0;
112   iy[1] = 1;
113 
114   PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 2, ix, PETSC_COPY_VALUES, &isx));
115   PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 2, iy, PETSC_COPY_VALUES, &isy));
116 
117   PetscCall(VecScatterCreate(x, isx, y, isy, &ctx));
118   /* Call SetUp explicitly, otherwise messages in implicit SetUp will be counted in events below */
119   PetscCall(VecScatterSetUp(ctx));
120 
121   PetscCall(PetscLogStagePush(stage2));
122   PetscCall(PetscLogEventBegin(event2, 0, 0, 0, 0));
123   errors = 0;
124   for (i = 0; i < niter; i++) {
125     /* set x = 0+i, 1+i, 2+i, ..., N-1+i */
126     PetscCall(VecGetArray(x, &xval));
127     for (j = 0; j < n; j++) xval[j] = (PetscScalar)(low + j + i);
128     PetscCall(VecRestoreArray(x, &xval));
129     /* scatter the ghost blocks to y */
130     PetscCall(VecScatterBegin(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
131     PetscCall(VecScatterEnd(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
132     /* check if y has correct values */
133     PetscCall(VecGetArrayRead(y, &yval));
134     if ((PetscInt)PetscRealPart(yval[0]) != ix[0] * bs + i) errors++;
135     if ((PetscInt)PetscRealPart(yval[bs]) != ix[1] * bs + i) errors++;
136     PetscCall(VecRestoreArrayRead(y, &yval));
137   }
138   PetscCall(PetscLogEventEnd(event2, 0, 0, 0, 0));
139   PetscCall(PetscLogStagePop());
140 
141   /* check if we found wrong values on any processors */
142   PetscCall(MPIU_Allreduce(&errors, &tot_errors, 1, MPIU_INT, MPI_SUM, PETSC_COMM_WORLD));
143   if (tot_errors) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error: wrong values were scatterred in vecscatter with bs = %" PetscInt_FMT "\n", bs));
144 
145     /* print out event log of VecScatter(bs=4) */
146 #if defined(PETSC_USE_LOG)
147   PetscCall(PetscLogEventGetPerfInfo(stage2, event2, &eventInfo));
148   PetscCall(MPIU_Allreduce(&eventInfo.numMessages, &numMessages, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, PETSC_COMM_WORLD));
149   PetscCall(MPIU_Allreduce(&eventInfo.messageLength, &messageLength, 1, MPIU_PETSCLOGDOUBLE, MPI_SUM, PETSC_COMM_WORLD));
150   tot_msg = (PetscInt)numMessages * 0.5; /* two MPI calls (Send & Recv) per message */
151   tot_len = (PetscInt)messageLength * 0.5;
152   avg_len = tot_msg ? (PetscInt)(messageLength / numMessages) : 0;
153   /* when nproc > 2, tot_msg = 2*nproc*niter, tot_len = tot_msg*sizeof(PetscScalar)*bs */
154   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "VecScatter(bs=%" PetscInt_FMT ") has sent out %" PetscInt_FMT " messages, total %" PetscInt_FMT " bytes, with average length %" PetscInt_FMT " bytes\n", bs, tot_msg, tot_len, avg_len));
155 #endif
156 
157   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Program finished\n"));
158   PetscCall(ISDestroy(&isx));
159   PetscCall(ISDestroy(&isy));
160   PetscCall(VecScatterDestroy(&ctx));
161   PetscCall(VecDestroy(&x));
162   PetscCall(VecDestroy(&y));
163   PetscCall(PetscFinalize());
164   return 0;
165 }
166 
167 /*TEST
168 
169    test:
170       nsize: 4
171       args:
172       requires: double defined(PETSC_USE_LOG)
173 
174 TEST*/
175