xref: /petsc/src/mat/tests/ex57.c (revision dfd57a172ac9fa6c7b5fe6de6ab5df85cefc2996)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Reads in a binary file, extracts a submatrix from it, and writes to another binary file.\n\
3c4762a1bSJed Brown Options:\n\
4c4762a1bSJed Brown   -fin  <mat>  : input matrix file\n\
5c4762a1bSJed Brown   -fout <mat>  : output marrix file\n\
6c4762a1bSJed Brown   -start <row> : the row from where the submat should be extracted\n\
7c4762a1bSJed Brown   -m  <sx>  : the size of the submatrix\n";
8c4762a1bSJed Brown 
9c4762a1bSJed Brown #include <petscmat.h>
10c4762a1bSJed Brown #include <petscvec.h>
11c4762a1bSJed Brown 
12c4762a1bSJed Brown int main(int argc,char **args)
13c4762a1bSJed Brown {
14c4762a1bSJed Brown   char           fin[PETSC_MAX_PATH_LEN],fout[PETSC_MAX_PATH_LEN] ="default.mat";
15c4762a1bSJed Brown   PetscViewer    fdin,fdout;
16c4762a1bSJed Brown   Vec            b;
17c4762a1bSJed Brown   MatType        mtype = MATSEQBAIJ;
18c4762a1bSJed Brown   Mat            A,*B;
19c4762a1bSJed Brown   PetscErrorCode ierr;
20c4762a1bSJed Brown   PetscInt       start=0;
21c4762a1bSJed Brown   PetscInt       m;
22c4762a1bSJed Brown   IS             isrow,iscol;
23c4762a1bSJed Brown   PetscBool      flg;
24c4762a1bSJed Brown 
25c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
26589a23caSBarry Smith   ierr = PetscOptionsGetString(NULL,NULL,"-fin",fin,sizeof(fin),&flg);CHKERRQ(ierr);
27c4762a1bSJed Brown   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -fin option");
28c4762a1bSJed Brown   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,fin,FILE_MODE_READ,&fdin);CHKERRQ(ierr);
29c4762a1bSJed Brown 
30589a23caSBarry Smith   ierr = PetscOptionsGetString(NULL,NULL,"-fout",fout,sizeof(fout),&flg);CHKERRQ(ierr);
31c4762a1bSJed Brown   if (!flg) {ierr = PetscPrintf(PETSC_COMM_WORLD,"Writing submatrix to file : %s\n",fout);CHKERRQ(ierr);}
32c4762a1bSJed Brown   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,fout,FILE_MODE_WRITE,&fdout);CHKERRQ(ierr);
33c4762a1bSJed Brown 
34c4762a1bSJed Brown   ierr = MatCreate(PETSC_COMM_SELF,&A);CHKERRQ(ierr);
35c4762a1bSJed Brown   ierr = MatSetType(A,mtype);CHKERRQ(ierr);
36c4762a1bSJed Brown   ierr = MatLoad(A,fdin);CHKERRQ(ierr);
37c4762a1bSJed Brown   ierr = PetscViewerDestroy(&fdin);CHKERRQ(ierr);
38c4762a1bSJed Brown 
39c4762a1bSJed Brown   ierr  = MatGetSize(A,&m,&m);CHKERRQ(ierr);
40c4762a1bSJed Brown   m /= 2;
41c4762a1bSJed Brown   ierr  = PetscOptionsGetInt(NULL,NULL,"-start",&start,NULL);CHKERRQ(ierr);
42c4762a1bSJed Brown   ierr  = PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);CHKERRQ(ierr);
43c4762a1bSJed Brown 
44c4762a1bSJed Brown   ierr = ISCreateStride(PETSC_COMM_SELF,m,start,1,&isrow);CHKERRQ(ierr);
45c4762a1bSJed Brown   ierr = ISCreateStride(PETSC_COMM_SELF,m,start,1,&iscol);CHKERRQ(ierr);
46c4762a1bSJed Brown   ierr = MatCreateSubMatrices(A,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&B);CHKERRQ(ierr);
47c4762a1bSJed Brown   ierr = MatView(B[0],fdout);CHKERRQ(ierr);
48c4762a1bSJed Brown 
49c4762a1bSJed Brown   ierr = VecCreate(PETSC_COMM_SELF,&b);CHKERRQ(ierr);
50c4762a1bSJed Brown   ierr = VecSetSizes(b,PETSC_DECIDE,m);CHKERRQ(ierr);
51c4762a1bSJed Brown   ierr = VecSetFromOptions(b);CHKERRQ(ierr);
52c4762a1bSJed Brown   ierr = MatView(B[0],fdout);CHKERRQ(ierr);
53c4762a1bSJed Brown   ierr = PetscViewerDestroy(&fdout);CHKERRQ(ierr);
54c4762a1bSJed Brown 
55c4762a1bSJed Brown   ierr = MatDestroy(&A);CHKERRQ(ierr);
56c4762a1bSJed Brown   ierr = MatDestroy(&B[0]);CHKERRQ(ierr);
57c4762a1bSJed Brown   ierr = VecDestroy(&b);CHKERRQ(ierr);
58c4762a1bSJed Brown   ierr = PetscFree(B);CHKERRQ(ierr);
59c4762a1bSJed Brown   ierr = ISDestroy(&iscol);CHKERRQ(ierr);
60c4762a1bSJed Brown   ierr = ISDestroy(&isrow);CHKERRQ(ierr);
61c4762a1bSJed Brown   ierr = PetscFinalize();
62c4762a1bSJed Brown   return ierr;
63c4762a1bSJed Brown }
64c4762a1bSJed Brown 
65c4762a1bSJed Brown /*TEST
66c4762a1bSJed Brown 
67c4762a1bSJed Brown     test:
68c4762a1bSJed Brown       args: -fin ${DATAFILESPATH}/matrices/small -fout joe -start 2 -m 4
69*dfd57a17SPierre Jolivet       requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
70c4762a1bSJed Brown 
71c4762a1bSJed Brown TEST*/
72c4762a1bSJed Brown 
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