xref: /petsc/src/mat/tests/ex57.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown 
2*c4762a1bSJed Brown static char help[] = "Reads in a binary file, extracts a submatrix from it, and writes to another binary file.\n\
3*c4762a1bSJed Brown Options:\n\
4*c4762a1bSJed Brown   -fin  <mat>  : input matrix file\n\
5*c4762a1bSJed Brown   -fout <mat>  : output marrix file\n\
6*c4762a1bSJed Brown   -start <row> : the row from where the submat should be extracted\n\
7*c4762a1bSJed Brown   -m  <sx>  : the size of the submatrix\n";
8*c4762a1bSJed Brown 
9*c4762a1bSJed Brown #include <petscmat.h>
10*c4762a1bSJed Brown #include <petscvec.h>
11*c4762a1bSJed Brown 
12*c4762a1bSJed Brown int main(int argc,char **args)
13*c4762a1bSJed Brown {
14*c4762a1bSJed Brown   char           fin[PETSC_MAX_PATH_LEN],fout[PETSC_MAX_PATH_LEN] ="default.mat";
15*c4762a1bSJed Brown   PetscViewer    fdin,fdout;
16*c4762a1bSJed Brown   Vec            b;
17*c4762a1bSJed Brown   MatType        mtype = MATSEQBAIJ;
18*c4762a1bSJed Brown   Mat            A,*B;
19*c4762a1bSJed Brown   PetscErrorCode ierr;
20*c4762a1bSJed Brown   PetscInt       start=0;
21*c4762a1bSJed Brown   PetscInt       m;
22*c4762a1bSJed Brown   IS             isrow,iscol;
23*c4762a1bSJed Brown   PetscBool      flg;
24*c4762a1bSJed Brown 
25*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
26*c4762a1bSJed Brown   ierr = PetscOptionsGetString(NULL,NULL,"-fin",fin,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
27*c4762a1bSJed Brown   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -fin option");
28*c4762a1bSJed Brown   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,fin,FILE_MODE_READ,&fdin);CHKERRQ(ierr);
29*c4762a1bSJed Brown 
30*c4762a1bSJed Brown   ierr = PetscOptionsGetString(NULL,NULL,"-fout",fout,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
31*c4762a1bSJed Brown   if (!flg) {ierr = PetscPrintf(PETSC_COMM_WORLD,"Writing submatrix to file : %s\n",fout);CHKERRQ(ierr);}
32*c4762a1bSJed Brown   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,fout,FILE_MODE_WRITE,&fdout);CHKERRQ(ierr);
33*c4762a1bSJed Brown 
34*c4762a1bSJed Brown   ierr = MatCreate(PETSC_COMM_SELF,&A);CHKERRQ(ierr);
35*c4762a1bSJed Brown   ierr = MatSetType(A,mtype);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = MatLoad(A,fdin);CHKERRQ(ierr);
37*c4762a1bSJed Brown   ierr = PetscViewerDestroy(&fdin);CHKERRQ(ierr);
38*c4762a1bSJed Brown 
39*c4762a1bSJed Brown   ierr  = MatGetSize(A,&m,&m);CHKERRQ(ierr);
40*c4762a1bSJed Brown   m /= 2;
41*c4762a1bSJed Brown   ierr  = PetscOptionsGetInt(NULL,NULL,"-start",&start,NULL);CHKERRQ(ierr);
42*c4762a1bSJed Brown   ierr  = PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);CHKERRQ(ierr);
43*c4762a1bSJed Brown 
44*c4762a1bSJed Brown   ierr = ISCreateStride(PETSC_COMM_SELF,m,start,1,&isrow);CHKERRQ(ierr);
45*c4762a1bSJed Brown   ierr = ISCreateStride(PETSC_COMM_SELF,m,start,1,&iscol);CHKERRQ(ierr);
46*c4762a1bSJed Brown   ierr = MatCreateSubMatrices(A,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&B);CHKERRQ(ierr);
47*c4762a1bSJed Brown   ierr = MatView(B[0],fdout);CHKERRQ(ierr);
48*c4762a1bSJed Brown 
49*c4762a1bSJed Brown   ierr = VecCreate(PETSC_COMM_SELF,&b);CHKERRQ(ierr);
50*c4762a1bSJed Brown   ierr = VecSetSizes(b,PETSC_DECIDE,m);CHKERRQ(ierr);
51*c4762a1bSJed Brown   ierr = VecSetFromOptions(b);CHKERRQ(ierr);
52*c4762a1bSJed Brown   ierr = MatView(B[0],fdout);CHKERRQ(ierr);
53*c4762a1bSJed Brown   ierr = PetscViewerDestroy(&fdout);CHKERRQ(ierr);
54*c4762a1bSJed Brown 
55*c4762a1bSJed Brown   ierr = MatDestroy(&A);CHKERRQ(ierr);
56*c4762a1bSJed Brown   ierr = MatDestroy(&B[0]);CHKERRQ(ierr);
57*c4762a1bSJed Brown   ierr = VecDestroy(&b);CHKERRQ(ierr);
58*c4762a1bSJed Brown   ierr = PetscFree(B);CHKERRQ(ierr);
59*c4762a1bSJed Brown   ierr = ISDestroy(&iscol);CHKERRQ(ierr);
60*c4762a1bSJed Brown   ierr = ISDestroy(&isrow);CHKERRQ(ierr);
61*c4762a1bSJed Brown   ierr = PetscFinalize();
62*c4762a1bSJed Brown   return ierr;
63*c4762a1bSJed Brown }
64*c4762a1bSJed Brown 
65*c4762a1bSJed Brown /*TEST
66*c4762a1bSJed Brown 
67*c4762a1bSJed Brown     test:
68*c4762a1bSJed Brown       args: -fin ${DATAFILESPATH}/matrices/small -fout joe -start 2 -m 4
69*c4762a1bSJed Brown       requires: datafilespath double !complex !define(PETSC_USE_64BIT_INDICES)
70*c4762a1bSJed Brown 
71*c4762a1bSJed Brown TEST*/
72*c4762a1bSJed Brown 
73