1 static char help[] = "Check the difference of the two matrices \n\ 2 Reads PETSc matrix A and B, then check B=A-B \n\ 3 Input parameters include\n\ 4 -fA <input_file> -fB <input_file> \n\n"; 5 6 #include <petscmat.h> 7 8 int main(int argc, char **args) { 9 Mat A, B; 10 PetscViewer fd; 11 char file[2][PETSC_MAX_PATH_LEN]; 12 PetscBool flg; 13 PetscMPIInt size; 14 PetscInt ma, na, mb, nb; 15 16 PetscFunctionBeginUser; 17 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 18 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 19 PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uniprocessor example only!"); 20 21 /* read the two matrices, A and B */ 22 PetscCall(PetscOptionsGetString(NULL, NULL, "-fA", file[0], sizeof(file[0]), &flg)); 23 PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -fA options"); 24 PetscCall(PetscOptionsGetString(NULL, NULL, "-fB", file[1], sizeof(file[1]), &flg)); 25 PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -fP options"); 26 27 /* Load matrices */ 28 PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, file[0], FILE_MODE_READ, &fd)); 29 PetscCall(MatCreate(PETSC_COMM_WORLD, &A)); 30 PetscCall(MatLoad(A, fd)); 31 PetscCall(PetscViewerDestroy(&fd)); 32 printf("\n A:\n"); 33 printf("----------------------\n"); 34 PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD)); 35 PetscCall(MatGetSize(A, &ma, &na)); 36 37 PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, file[1], FILE_MODE_READ, &fd)); 38 PetscCall(MatCreate(PETSC_COMM_WORLD, &B)); 39 PetscCall(MatLoad(B, fd)); 40 PetscCall(PetscViewerDestroy(&fd)); 41 printf("\n B:\n"); 42 printf("----------------------\n"); 43 PetscCall(MatView(B, PETSC_VIEWER_STDOUT_WORLD)); 44 PetscCall(MatGetSize(B, &mb, &nb)); 45 46 /* Compute B = -A + B */ 47 PetscCheck(ma == mb && na == nb, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "nonconforming matrix size"); 48 PetscCall(MatAXPY(B, -1.0, A, DIFFERENT_NONZERO_PATTERN)); 49 printf("\n B - A:\n"); 50 printf("----------------------\n"); 51 PetscCall(MatView(B, PETSC_VIEWER_STDOUT_WORLD)); 52 53 PetscCall(MatDestroy(&B)); 54 PetscCall(MatDestroy(&A)); 55 PetscCall(PetscFinalize()); 56 return 0; 57 } 58