1 2 static char help[]= "Scatters from a parallel vector to a sequential vector. \n\ 3 uses block index sets\n\n"; 4 5 #include <petscvec.h> 6 7 int main(int argc,char **argv) 8 { 9 PetscErrorCode ierr; 10 PetscInt bs=1,n=5,i,low; 11 PetscInt ix0[3] = {5,7,9},iy0[3] = {1,2,4},ix1[3] = {2,3,4},iy1[3] = {0,1,3}; 12 PetscMPIInt size,rank; 13 PetscScalar *array; 14 Vec x,y; 15 IS isx,isy; 16 VecScatter ctx; 17 18 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 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(VecSet(y,0.0)); 42 43 /* Create two index sets */ 44 if (rank == 0) { 45 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,ix0,PETSC_COPY_VALUES,&isx)); 46 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,iy0,PETSC_COPY_VALUES,&isy)); 47 } else { 48 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,ix1,PETSC_COPY_VALUES,&isx)); 49 CHKERRQ(ISCreateBlock(PETSC_COMM_SELF,bs,3,iy1,PETSC_COPY_VALUES,&isy)); 50 } 51 52 if (rank == 10) { 53 CHKERRQ(PetscPrintf(PETSC_COMM_SELF,"\n[%d] isx:\n",rank)); 54 CHKERRQ(ISView(isx,PETSC_VIEWER_STDOUT_SELF)); 55 } 56 57 CHKERRQ(VecScatterCreate(x,isx,y,isy,&ctx)); 58 CHKERRQ(VecScatterSetFromOptions(ctx)); 59 60 /* Test forward vecscatter */ 61 CHKERRQ(VecScatterBegin(ctx,x,y,ADD_VALUES,SCATTER_FORWARD)); 62 CHKERRQ(VecScatterEnd(ctx,x,y,ADD_VALUES,SCATTER_FORWARD)); 63 if (rank == 0) { 64 CHKERRQ(PetscPrintf(PETSC_COMM_SELF,"[%d] y:\n",rank)); 65 CHKERRQ(VecView(y,PETSC_VIEWER_STDOUT_SELF)); 66 } 67 68 /* Test reverse vecscatter */ 69 CHKERRQ(VecScale(y,-1.0)); 70 if (rank) { 71 CHKERRQ(VecScale(y,1.0/(size - 1))); 72 } 73 74 CHKERRQ(VecScatterBegin(ctx,y,x,ADD_VALUES,SCATTER_REVERSE)); 75 CHKERRQ(VecScatterEnd(ctx,y,x,ADD_VALUES,SCATTER_REVERSE)); 76 CHKERRQ(VecView(x,PETSC_VIEWER_STDOUT_WORLD)); 77 78 /* Free spaces */ 79 CHKERRQ(VecScatterDestroy(&ctx)); 80 CHKERRQ(ISDestroy(&isx)); 81 CHKERRQ(ISDestroy(&isy)); 82 CHKERRQ(VecDestroy(&x)); 83 CHKERRQ(VecDestroy(&y)); 84 ierr = PetscFinalize(); 85 return ierr; 86 } 87 88 /*TEST 89 90 test: 91 nsize: 3 92 93 TEST*/ 94