xref: /petsc/src/vec/is/sf/tests/ex14.c (revision ebead697dbf761eb322f829370bbe90b3bd93fa3)
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   PetscCallMPI(MPI_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   PetscCallMPI(MPI_Allreduce(&eventInfo.numMessages,  &numMessages,  1,MPIU_PETSCLOGDOUBLE,MPI_SUM,PETSC_COMM_WORLD));
91   PetscCallMPI(MPI_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   PetscCallMPI(MPI_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   PetscCallMPI(MPI_Allreduce(&eventInfo.numMessages,  &numMessages,  1,MPIU_PETSCLOGDOUBLE,MPI_SUM,PETSC_COMM_WORLD));
149   PetscCallMPI(MPI_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