xref: /petsc/src/mat/tests/ex57.c (revision b122ec5aa1bd4469eb4e0673542fb7de3f411254)
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   PetscInt       start=0;
20c4762a1bSJed Brown   PetscInt       m;
21c4762a1bSJed Brown   IS             isrow,iscol;
22c4762a1bSJed Brown   PetscBool      flg;
23c4762a1bSJed Brown 
24*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscInitialize(&argc,&args,(char*)0,help));
255f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetString(NULL,NULL,"-fin",fin,sizeof(fin),&flg));
2628b400f6SJacob Faibussowitsch   PetscCheck(flg,PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -fin option");
275f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerBinaryOpen(PETSC_COMM_SELF,fin,FILE_MODE_READ,&fdin));
28c4762a1bSJed Brown 
295f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetString(NULL,NULL,"-fout",fout,sizeof(fout),&flg));
305f80ce2aSJacob Faibussowitsch   if (!flg) CHKERRQ(PetscPrintf(PETSC_COMM_WORLD,"Writing submatrix to file : %s\n",fout));
315f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerBinaryOpen(PETSC_COMM_SELF,fout,FILE_MODE_WRITE,&fdout));
32c4762a1bSJed Brown 
335f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreate(PETSC_COMM_SELF,&A));
345f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetType(A,mtype));
355f80ce2aSJacob Faibussowitsch   CHKERRQ(MatLoad(A,fdin));
365f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerDestroy(&fdin));
37c4762a1bSJed Brown 
385f80ce2aSJacob Faibussowitsch   CHKERRQ(MatGetSize(A,&m,&m));
39c4762a1bSJed Brown   m /= 2;
405f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-start",&start,NULL));
415f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
42c4762a1bSJed Brown 
435f80ce2aSJacob Faibussowitsch   CHKERRQ(ISCreateStride(PETSC_COMM_SELF,m,start,1,&isrow));
445f80ce2aSJacob Faibussowitsch   CHKERRQ(ISCreateStride(PETSC_COMM_SELF,m,start,1,&iscol));
455f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreateSubMatrices(A,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&B));
465f80ce2aSJacob Faibussowitsch   CHKERRQ(MatView(B[0],fdout));
47c4762a1bSJed Brown 
485f80ce2aSJacob Faibussowitsch   CHKERRQ(VecCreate(PETSC_COMM_SELF,&b));
495f80ce2aSJacob Faibussowitsch   CHKERRQ(VecSetSizes(b,PETSC_DECIDE,m));
505f80ce2aSJacob Faibussowitsch   CHKERRQ(VecSetFromOptions(b));
515f80ce2aSJacob Faibussowitsch   CHKERRQ(MatView(B[0],fdout));
525f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerDestroy(&fdout));
53c4762a1bSJed Brown 
545f80ce2aSJacob Faibussowitsch   CHKERRQ(MatDestroy(&A));
555f80ce2aSJacob Faibussowitsch   CHKERRQ(MatDestroy(&B[0]));
565f80ce2aSJacob Faibussowitsch   CHKERRQ(VecDestroy(&b));
575f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscFree(B));
585f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&iscol));
595f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&isrow));
60*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscFinalize());
61*b122ec5aSJacob Faibussowitsch   return 0;
62c4762a1bSJed Brown }
63c4762a1bSJed Brown 
64c4762a1bSJed Brown /*TEST
65c4762a1bSJed Brown 
66c4762a1bSJed Brown     test:
67c4762a1bSJed Brown       args: -fin ${DATAFILESPATH}/matrices/small -fout joe -start 2 -m 4
68dfd57a17SPierre Jolivet       requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
69c4762a1bSJed Brown 
70c4762a1bSJed Brown TEST*/
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