1 2 static char help[] = "Saves 4by4 block matrix.\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat A; 9 PetscInt i,j; 10 PetscMPIInt size; 11 PetscViewer fd; 12 PetscScalar values[16],one = 1.0; 13 Vec x; 14 15 PetscFunctionBeginUser; 16 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 17 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 18 PetscCheck(size == 1,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,m"Can only run on one processor"); 19 20 /* 21 Open binary file. Note that we use FILE_MODE_WRITE to indicate 22 writing to this file. 23 */ 24 PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,"4by4",FILE_MODE_WRITE,&fd)); 25 26 PetscCall(MatCreateSeqBAIJ(PETSC_COMM_WORLD,4,12,12,0,0,&A)); 27 28 for (i=0; i<16; i++) values[i] = i; 29 for (i=0; i<4; i++) values[4*i+i] += 5; 30 i = 0; j = 0; 31 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 32 33 for (i=0; i<16; i++) values[i] = i; 34 i = 0; j = 2; 35 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 36 37 for (i=0; i<16; i++) values[i] = i; 38 i = 1; j = 0; 39 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 40 41 for (i=0; i<16; i++) values[i] = i;for (i=0; i<4; i++) values[4*i+i] += 6; 42 i = 1; j = 1; 43 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 44 45 for (i=0; i<16; i++) values[i] = i; 46 i = 2; j = 0; 47 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 48 49 for (i=0; i<16; i++) values[i] = i;for (i=0; i<4; i++) values[4*i+i] += 7; 50 i = 2; j = 2; 51 PetscCall(MatSetValuesBlocked(A,1,&i,1,&j,values,INSERT_VALUES)); 52 53 PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY)); 54 PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY)); 55 PetscCall(MatView(A,fd)); 56 PetscCall(MatDestroy(&A)); 57 58 PetscCall(VecCreateSeq(PETSC_COMM_WORLD,12,&x)); 59 PetscCall(VecSet(x,one)); 60 PetscCall(VecView(x,fd)); 61 PetscCall(VecDestroy(&x)); 62 63 PetscCall(PetscViewerDestroy(&fd)); 64 PetscCall(PetscFinalize()); 65 return 0; 66 } 67