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