1 static char help[] = "Scatters from a parallel vector to a sequential vector.\n\ 2 Tests where the local part of the scatter is a copy.\n\n"; 3 4 #include <petscvec.h> 5 6 int main(int argc, char **argv) 7 { 8 PetscMPIInt size, rank; 9 PetscInt n = 5, i, *blks, bs = 1, m = 2; 10 PetscScalar value; 11 Vec x, y; 12 IS is1, is2; 13 VecScatter ctx = 0; 14 PetscViewer sviewer; 15 16 PetscFunctionBeginUser; 17 PetscCall(PetscInitialize(&argc, &argv, (char *)0, help)); 18 19 PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL)); 20 PetscCall(PetscOptionsGetInt(NULL, NULL, "-bs", &bs, NULL)); 21 22 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 23 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 24 25 /* create two vectors */ 26 PetscCall(VecCreate(PETSC_COMM_WORLD, &x)); 27 PetscCall(VecSetSizes(x, PETSC_DECIDE, size * bs * n)); 28 PetscCall(VecSetFromOptions(x)); 29 30 /* create two index sets */ 31 if (rank < size - 1) m = n + 2; 32 else m = n; 33 34 PetscCall(PetscMalloc1(m, &blks)); 35 blks[0] = n * rank; 36 for (i = 1; i < m; i++) blks[i] = blks[i - 1] + 1; 37 PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, m, blks, PETSC_COPY_VALUES, &is1)); 38 PetscCall(PetscFree(blks)); 39 40 PetscCall(VecCreateSeq(PETSC_COMM_SELF, bs * m, &y)); 41 PetscCall(ISCreateStride(PETSC_COMM_SELF, bs * m, 0, 1, &is2)); 42 43 /* each processor inserts the entire vector */ 44 /* this is redundant but tests assembly */ 45 for (i = 0; i < bs * n * size; i++) { 46 value = (PetscScalar)i; 47 PetscCall(VecSetValues(x, 1, &i, &value, INSERT_VALUES)); 48 } 49 PetscCall(VecAssemblyBegin(x)); 50 PetscCall(VecAssemblyEnd(x)); 51 PetscCall(VecView(x, PETSC_VIEWER_STDOUT_WORLD)); 52 53 PetscCall(VecScatterCreate(x, is1, y, is2, &ctx)); 54 PetscCall(VecScatterBegin(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD)); 55 PetscCall(VecScatterEnd(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD)); 56 57 PetscCall(PetscViewerASCIIPushSynchronized(PETSC_VIEWER_STDOUT_WORLD)); 58 PetscCall(PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_WORLD, "----\n")); 59 PetscCall(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer)); 60 PetscCall(VecView(y, sviewer)); 61 PetscCall(PetscFFlush(PETSC_STDOUT)); 62 PetscCall(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer)); 63 PetscCall(PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD)); 64 PetscCall(PetscViewerASCIIPopSynchronized(PETSC_VIEWER_STDOUT_WORLD)); 65 66 PetscCall(VecScatterDestroy(&ctx)); 67 68 PetscCall(VecDestroy(&x)); 69 PetscCall(VecDestroy(&y)); 70 PetscCall(ISDestroy(&is1)); 71 PetscCall(ISDestroy(&is2)); 72 73 PetscCall(PetscFinalize()); 74 return 0; 75 } 76 77 /*TEST 78 79 testset: 80 nsize: 3 81 output_file: output/ex24_1.out 82 filter: grep -v " type:" 83 test: 84 suffix: standard 85 args: -vec_type standard 86 test: 87 requires: cuda 88 suffix: cuda 89 args: -vec_type cuda 90 test: 91 requires: viennacl 92 suffix: viennacl 93 args: -vec_type viennacl 94 95 TEST*/ 96