1 2 static char help[]= "Scatters from a sequential vector to a parallel vector. \n\ 3 uses block index sets\n\n"; 4 5 #include <petscvec.h> 6 7 int main(int argc,char **argv) 8 { 9 PetscInt bs=1,n=5,i,low; 10 PetscInt ix0[3] = {5,7,9},iy0[3] = {1,2,4},ix1[3] = {2,3,4},iy1[3] = {0,1,3}; 11 PetscMPIInt size,rank; 12 PetscScalar *array; 13 Vec x,y; 14 IS isx,isy; 15 VecScatter ctx; 16 PetscViewer sviewer; 17 18 CHKERRQ(PetscInitialize(&argc,&argv,(char*)0,help)); 19 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 20 CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 21 22 PetscCheckFalse(size <2,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"Must run more than one processor"); 23 24 CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-bs",&bs,NULL)); 25 n = bs*n; 26 27 /* Create vector x over shared memory */ 28 CHKERRQ(VecCreate(PETSC_COMM_WORLD,&x)); 29 CHKERRQ(VecSetSizes(x,n,PETSC_DECIDE)); 30 CHKERRQ(VecSetFromOptions(x)); 31 32 CHKERRQ(VecGetOwnershipRange(x,&low,NULL)); 33 CHKERRQ(VecGetArray(x,&array)); 34 for (i=0; i<n; i++) { 35 array[i] = (PetscScalar)(i + low); 36 } 37 CHKERRQ(VecRestoreArray(x,&array)); 38 39 /* Create a sequential vector y */ 40 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,n,&y)); 41 CHKERRQ(VecGetArray(y,&array)); 42 for (i=0; i<n; i++) { 43 array[i] = (PetscScalar)(i + 100*rank); 44 } 45 CHKERRQ(VecRestoreArray(y,&array)); 46 47 /* Create two index sets */ 48 if (rank == 0) { 49 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,ix0,PETSC_COPY_VALUES,&isx)); 50 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,iy0,PETSC_COPY_VALUES,&isy)); 51 } else { 52 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,ix1,PETSC_COPY_VALUES,&isx)); 53 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,iy1,PETSC_COPY_VALUES,&isy)); 54 } 55 56 if (rank == 10) { 57 CHKERRQ(PetscPrintf(PETSC_COMM_SELF,"\n[%d] isx:\n",rank)); 58 CHKERRQ(ISView(isx,PETSC_VIEWER_STDOUT_SELF)); 59 } 60 61 CHKERRQ(VecScatterCreate(y,isy,x,isx,&ctx)); 62 CHKERRQ(VecScatterSetFromOptions(ctx)); 63 64 /* Test forward vecscatter */ 65 CHKERRQ(VecSet(x,0.0)); 66 CHKERRQ(VecScatterBegin(ctx,y,x,ADD_VALUES,SCATTER_FORWARD)); 67 CHKERRQ(VecScatterEnd(ctx,y,x,ADD_VALUES,SCATTER_FORWARD)); 68 CHKERRQ(VecView(x,PETSC_VIEWER_STDOUT_WORLD)); 69 70 /* Test reverse vecscatter */ 71 CHKERRQ(VecScale(x,-1.0)); 72 CHKERRQ(VecScatterBegin(ctx,x,y,ADD_VALUES,SCATTER_REVERSE)); 73 CHKERRQ(VecScatterEnd(ctx,x,y,ADD_VALUES,SCATTER_REVERSE)); 74 CHKERRQ(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer)); 75 if (rank == 1) { 76 CHKERRQ(VecView(y,sviewer)); 77 } 78 CHKERRQ(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer)); 79 80 /* Free spaces */ 81 CHKERRQ(VecScatterDestroy(&ctx)); 82 CHKERRQ(ISDestroy(&isx)); 83 CHKERRQ(ISDestroy(&isy)); 84 CHKERRQ(VecDestroy(&x)); 85 CHKERRQ(VecDestroy(&y)); 86 CHKERRQ(PetscFinalize()); 87 return 0; 88 } 89 90 /*TEST 91 92 test: 93 nsize: 3 94 95 TEST*/ 96