xref: /petsc/src/mat/tests/ex171.c (revision 6a98f8dc3f2c9149905a87dc2e9d0fedaf64e09a)
1 
2 static char help[] = "Tests MatDiagonalSet() on MatLoad() matrix \n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc,char **args)
7 {
8   Mat            A;
9   Vec            x;
10   PetscErrorCode ierr;
11   PetscViewer    fd;              /* viewer */
12   char           file[PETSC_MAX_PATH_LEN]; /* input file name */
13   PetscReal      norm;
14   PetscBool      flg;
15 
16   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
17   /* Determine file from which we read the matrix A */
18   ierr = PetscOptionsGetString(NULL,NULL,"-f",file,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
19   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f option");
20 
21   /* Load matrix A */
22   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);CHKERRQ(ierr);
23   ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
24   ierr = MatLoad(A,fd);CHKERRQ(ierr);
25   ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
26   ierr = MatCreateVecs(A,&x,NULL);CHKERRQ(ierr);
27   ierr = MatGetDiagonal(A,x);CHKERRQ(ierr);
28   ierr = VecScale(x,-1.0);CHKERRQ(ierr);
29   ierr = MatDiagonalSet(A,x,ADD_VALUES);CHKERRQ(ierr);
30   ierr = MatGetDiagonal(A,x);CHKERRQ(ierr);
31   ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
32   ierr = PetscPrintf(PETSC_COMM_WORLD,"Norm %g\n",(double)norm);CHKERRQ(ierr);
33 
34   /* Free data structures */
35   ierr = MatDestroy(&A);CHKERRQ(ierr);
36   ierr = VecDestroy(&x);CHKERRQ(ierr);
37   ierr = PetscFinalize();
38   return ierr;
39 }
40 
41 
42 /*TEST
43 
44    test:
45       nsize: 4
46       requires: datafilespath !complex double !define(PETSC_USE_64BIT_INDICES)
47       args: -f ${wPETSC_DIR}/share/petsc/datafiles/matrices/ns-real-int32-float64 -malloc_dump
48 
49 TEST*/
50