Actual source code: ex12.c

      2: static char help[] = "Reads a PETSc matrix and vector from a file; expands the matrix with the vector\n\n";

      4: /*T
      5:    Concepts: Mat^ordering a matrix - loading a binary matrix and vector;
      6:    Concepts: Mat^loading a binary matrix and vector;
      7:    Concepts: Vectors^loading a binary vector;
      8:    Concepts: PetscLog^preloading executable
      9:    Processors: 1
     10: T*/

     14: /*
     15:   Include "petscmat.h" so that we can use matrices.
     16:   automatically includes:
     17:      petscsys.h       - base PETSc routines   petscvec.h    - vectors
     18:      petscmat.h    - matrices
     19:      petscis.h     - index sets            petscviewer.h - viewers
     20: */
     21: #include <petscmat.h>

     23: /*

     25:    Adds a new column and row to the vector (the last) containing the vector
     26: */
     27: PetscErrorCode PadMatrix(Mat A,Vec v,PetscScalar c,Mat *B)
     28: {
     29:   PetscErrorCode    ierr;
     30:   PetscInt          n,i,*cnt,*indices,nc;
     31:   const PetscInt    *aj;
     32:   const PetscScalar *vv,*aa;

     35:   MatGetSize(A,&n,NULL);
     36:   VecGetArrayRead(v,&vv);
     37:   PetscMalloc1(n,&indices);
     38:   for (i=0; i<n; i++) indices[i] = i;

     40:   /* determine number of nonzeros per row in the new matrix */
     41:   PetscMalloc1(n+1,&cnt);
     42:   for (i=0; i<n; i++) {
     43:     MatGetRow(A,i,&nc,NULL,NULL);
     44:     cnt[i] = nc + (vv[i] != 0.0);
     45:     MatRestoreRow(A,i,&nc,NULL,NULL);
     46:   }
     47:   cnt[n] = 1;
     48:   for (i=0; i<n; i++) {
     49:     cnt[n] += (vv[i] != 0.0);
     50:   }
     51:   MatCreateSeqAIJ(PETSC_COMM_SELF,n+1,n+1,0,cnt,B);
     52:   MatSetOption(*B,MAT_IGNORE_ZERO_ENTRIES,PETSC_TRUE);

     54:   /* copy over the matrix entries from the matrix and then the vector */
     55:   for (i=0; i<n; i++) {
     56:     MatGetRow(A,i,&nc,&aj,&aa);
     57:     MatSetValues(*B,1,&i,nc,aj,aa,INSERT_VALUES);
     58:     MatRestoreRow(A,i,&nc,&aj,&aa);
     59:   }
     60:   MatSetValues(*B,1,&n,n,indices,vv,INSERT_VALUES);
     61:   MatSetValues(*B,n,indices,1,&n,vv,INSERT_VALUES);
     62:   MatSetValues(*B,1,&n,1,&n,&c,INSERT_VALUES);

     64:   MatAssemblyBegin(*B,MAT_FINAL_ASSEMBLY);
     65:   MatAssemblyEnd(*B,MAT_FINAL_ASSEMBLY);
     66:   VecRestoreArrayRead(v,&vv);
     67:   PetscFree(cnt);
     68:   PetscFree(indices);
     69:   return(0);
     70: }

     73: int main(int argc,char **args)
     74: {
     75:   Mat            A,B;
     76:   PetscViewer    fd;                        /* viewer */
     77:   char           file[PETSC_MAX_PATH_LEN];  /* input file name */
     79:   PetscBool      flg;
     80:   Vec            v;

     82:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
     83:   /*
     84:      Determine files from which we read the two linear systems
     85:      (matrix and right-hand-side vector).
     86:   */
     87:   PetscOptionsGetString(NULL,NULL,"-f0",file,sizeof(file),&flg);
     88:   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f0 option");

     90:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);

     92:   MatCreate(PETSC_COMM_WORLD,&A);
     93:   MatSetType(A,MATSEQAIJ);
     94:   MatLoad(A,fd);
     95:   VecCreate(PETSC_COMM_WORLD,&v);
     96:   VecLoad(v,fd);
     97:   MatView(A,PETSC_VIEWER_STDOUT_SELF);
     98:   PadMatrix(A,v,3.0,&B);
     99:   MatView(B,PETSC_VIEWER_STDOUT_SELF);
    100:   MatDestroy(&B);
    101:   MatDestroy(&A);
    102:   VecDestroy(&v);
    103:   PetscViewerDestroy(&fd);

    105:   PetscFinalize();
    106:   return ierr;
    107: }

    111: /*TEST

    113:    test:
    114:       args: -f0 ${wPETSC_DIR}/share/petsc/datafiles/matrices/ns-real-int32-float64
    115:       requires: double !complex !define(PETSC_USE_64BIT_INDICES)

    117: TEST*/