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 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 PetscViewer sviewer; 18 19 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 20 ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRMPI(ierr); 21 ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr); 22 23 if (size <2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"Must run more than one processor"); 24 25 ierr = PetscOptionsGetInt(NULL,NULL,"-bs",&bs,NULL);CHKERRQ(ierr); 26 n = bs*n; 27 28 /* Create vector x over shared memory */ 29 ierr = VecCreate(PETSC_COMM_WORLD,&x);CHKERRQ(ierr); 30 ierr = VecSetSizes(x,n,PETSC_DECIDE);CHKERRQ(ierr); 31 ierr = VecSetFromOptions(x);CHKERRQ(ierr); 32 33 ierr = VecGetOwnershipRange(x,&low,NULL);CHKERRQ(ierr); 34 ierr = VecGetArray(x,&array);CHKERRQ(ierr); 35 for (i=0; i<n; i++) { 36 array[i] = (PetscScalar)(i + low); 37 } 38 ierr = VecRestoreArray(x,&array);CHKERRQ(ierr); 39 40 /* Create a sequential vector y */ 41 ierr = VecCreateSeq(PETSC_COMM_SELF,n,&y);CHKERRQ(ierr); 42 ierr = VecGetArray(y,&array);CHKERRQ(ierr); 43 for (i=0; i<n; i++) { 44 array[i] = (PetscScalar)(i + 100*rank); 45 } 46 ierr = VecRestoreArray(y,&array);CHKERRQ(ierr); 47 48 /* Create two index sets */ 49 if (!rank) { 50 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,3,ix0,PETSC_COPY_VALUES,&isx);CHKERRQ(ierr); 51 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,3,iy0,PETSC_COPY_VALUES,&isy);CHKERRQ(ierr); 52 } else { 53 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,3,ix1,PETSC_COPY_VALUES,&isx);CHKERRQ(ierr); 54 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,3,iy1,PETSC_COPY_VALUES,&isy);CHKERRQ(ierr); 55 } 56 57 if (rank == 10) { 58 ierr = PetscPrintf(PETSC_COMM_SELF,"\n[%d] isx:\n",rank);CHKERRQ(ierr); 59 ierr = ISView(isx,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 60 } 61 62 ierr = VecScatterCreate(y,isy,x,isx,&ctx);CHKERRQ(ierr); 63 ierr = VecScatterSetFromOptions(ctx);CHKERRQ(ierr); 64 65 /* Test forward vecscatter */ 66 ierr = VecSet(x,0.0);CHKERRQ(ierr); 67 ierr = VecScatterBegin(ctx,y,x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 68 ierr = VecScatterEnd(ctx,y,x,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 69 ierr = VecView(x,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 70 71 /* Test reverse vecscatter */ 72 ierr = VecScale(x,-1.0);CHKERRQ(ierr); 73 ierr = VecScatterBegin(ctx,x,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 74 ierr = VecScatterEnd(ctx,x,y,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr); 75 ierr = PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr); 76 if (rank == 1) { 77 ierr = VecView(y,sviewer);CHKERRQ(ierr); 78 } 79 ierr = PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr); 80 81 /* Free spaces */ 82 ierr = VecScatterDestroy(&ctx);CHKERRQ(ierr); 83 ierr = ISDestroy(&isx);CHKERRQ(ierr); 84 ierr = ISDestroy(&isy);CHKERRQ(ierr); 85 ierr = VecDestroy(&x);CHKERRQ(ierr); 86 ierr = VecDestroy(&y);CHKERRQ(ierr); 87 ierr = PetscFinalize(); 88 return ierr; 89 } 90 91 /*TEST 92 93 test: 94 nsize: 3 95 96 TEST*/ 97