1 static char help[]= "Test vecscatter of different block sizes across processes\n\n"; 2 3 #include <petscvec.h> 4 int main(int argc,char **argv) 5 { 6 PetscErrorCode ierr; 7 PetscInt i,bs,n,low,high; 8 PetscMPIInt nproc,rank; 9 Vec x,y,z; 10 IS ix,iy; 11 VecScatter vscat; 12 const PetscScalar *yv; 13 14 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 15 ierr = MPI_Comm_size(PETSC_COMM_WORLD,&nproc);CHKERRMPI(ierr); 16 ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr); 17 if (nproc != 2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This test can only run on two MPI ranks"); 18 19 /* Create an MPI vector x of size 12 on two processes, and set x = {0, 1, 2, .., 11} */ 20 ierr = VecCreateMPI(PETSC_COMM_WORLD,6,PETSC_DECIDE,&x);CHKERRQ(ierr); 21 ierr = VecGetOwnershipRange(x,&low,&high);CHKERRQ(ierr); 22 for (i=low; i<high; i++) {ierr = VecSetValue(x,i,(PetscScalar)i,INSERT_VALUES);CHKERRQ(ierr);} 23 ierr = VecAssemblyBegin(x);CHKERRQ(ierr); 24 ierr = VecAssemblyEnd(x);CHKERRQ(ierr); 25 26 /* Create a seq vector y, and a parallel to sequential (PtoS) vecscatter to scatter x to y */ 27 if (rank == 0) { 28 /* On rank 0, seq y is of size 6. We will scatter x[0,1,2,6,7,8] to y[0,1,2,3,4,5] using IS with bs=3 */ 29 PetscInt idx[2]={0,2}; 30 PetscInt idy[2]={0,1}; 31 n = 6; 32 bs = 3; 33 ierr = VecCreateSeq(PETSC_COMM_SELF,n,&y);CHKERRQ(ierr); 34 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,2,idx,PETSC_COPY_VALUES,&ix);CHKERRQ(ierr); 35 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,2,idy,PETSC_COPY_VALUES,&iy);CHKERRQ(ierr); 36 } else { 37 /* On rank 1, seq y is of size 4. We will scatter x[4,5,10,11] to y[0,1,2,3] using IS with bs=2 */ 38 PetscInt idx[2]= {2,5}; 39 PetscInt idy[2]= {0,1}; 40 n = 4; 41 bs = 2; 42 ierr = VecCreateSeq(PETSC_COMM_SELF,n,&y);CHKERRQ(ierr); 43 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,2,idx,PETSC_COPY_VALUES,&ix);CHKERRQ(ierr); 44 ierr = ISCreateBlock(PETSC_COMM_SELF,bs,2,idy,PETSC_COPY_VALUES,&iy);CHKERRQ(ierr); 45 } 46 ierr = VecScatterCreate(x,ix,y,iy,&vscat);CHKERRQ(ierr); 47 48 /* Do the vecscatter */ 49 ierr = VecScatterBegin(vscat,x,y,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 50 ierr = VecScatterEnd(vscat,x,y,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr); 51 52 /* Print y. Since y is sequential, we put y in a parallel z to print its value on both ranks */ 53 ierr = VecGetArrayRead(y,&yv);CHKERRQ(ierr); 54 ierr = VecCreateMPIWithArray(PETSC_COMM_WORLD,1,n,PETSC_DECIDE,yv,&z);CHKERRQ(ierr); 55 ierr = VecView(z,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 56 ierr = VecRestoreArrayRead(y,&yv);CHKERRQ(ierr); 57 58 ierr = ISDestroy(&ix);CHKERRQ(ierr); 59 ierr = ISDestroy(&iy);CHKERRQ(ierr); 60 ierr = VecDestroy(&x);CHKERRQ(ierr); 61 ierr = VecDestroy(&y);CHKERRQ(ierr); 62 ierr = VecDestroy(&z);CHKERRQ(ierr); 63 ierr = VecScatterDestroy(&vscat);CHKERRQ(ierr); 64 65 ierr = PetscFinalize(); 66 return ierr; 67 } 68 69 /*TEST 70 71 test: 72 nsize: 2 73 args: 74 requires: 75 TEST*/ 76 77