xref: /petsc/src/mat/tests/ex124.c (revision bef158480efac06de457f7a665168877ab3c2fd7)
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 #undef WRITEFILE
9 PetscInt main(PetscInt argc,char **args)
10 {
11   Mat            A,B;
12   PetscViewer    fd;
13   char           file[2][PETSC_MAX_PATH_LEN];
14   PetscBool      flg;
15   PetscErrorCode ierr;
16   PetscMPIInt    size;
17   PetscInt       ma,na,mb,nb;
18 
19   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
20   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
21   if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This is a uniprocessor example only!");
22 
23   /* read the two matrices, A and B */
24   ierr = PetscOptionsGetString(NULL,NULL,"-fA",file[0],sizeof(file[0]),&flg);CHKERRQ(ierr);
25   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -fA options");
26   ierr = PetscOptionsGetString(NULL,NULL,"-fB",file[1],sizeof(file[1]),&flg);CHKERRQ(ierr);
27   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -fP options");
28 
29   /* Load matrices */
30   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[0],FILE_MODE_READ,&fd);CHKERRQ(ierr);
31   ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
32   ierr = MatLoad(A,fd);CHKERRQ(ierr);
33   ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
34   printf("\n A:\n");
35   printf("----------------------\n");
36   ierr = MatView(A,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
37   ierr = MatGetSize(A,&ma,&na);CHKERRQ(ierr);
38 
39   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[1],FILE_MODE_READ,&fd);CHKERRQ(ierr);
40   ierr = MatCreate(PETSC_COMM_WORLD,&B);CHKERRQ(ierr);
41   ierr = MatLoad(B,fd);CHKERRQ(ierr);
42   ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
43   printf("\n B:\n");
44   printf("----------------------\n");
45   ierr = MatView(B,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
46   ierr = MatGetSize(B,&mb,&nb);CHKERRQ(ierr);
47 
48   /* Compute B = -A + B */
49   if (ma != mb || na != nb) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"nonconforming matrix size");
50   ierr = MatAXPY(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
51   printf("\n B - A:\n");
52   printf("----------------------\n");
53   ierr = MatView(B,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
54 
55   ierr = MatDestroy(&B);CHKERRQ(ierr);
56   ierr = MatDestroy(&A);CHKERRQ(ierr);
57   ierr = PetscFinalize();
58   return ierr;
59 }
60