xref: /petsc/src/mat/impls/baij/seq/aijbaij.c (revision 4a2ae208534dc2960f861bf8a1e27d424854347f)

/*$Id: aijbaij.c,v 1.6 2001/03/09 22:50:54 balay Exp balay $*/

#include "src/mat/impls/baij/seq/baij.h"

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "MatConvert_SeqBAI_SeqAIJ"
int MatConvert_SeqBAIJ_SeqAIJ(Mat A,MatType newtype,Mat *B)
{
  Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data;
  int         ierr,bs = a->bs,*ai = a->i,*aj = a->j,n = A->M/bs,i,j,k;
  int         *rowlengths,*rows,*cols,maxlen = 0,ncols;
  Scalar      *aa = a->a;

  PetscFunctionBegin;
  ierr = PetscMalloc(n*bs*sizeof(int),&rowlengths);CHKERRQ(ierr);
  for (i=0; i<n; i++) {
    maxlen = PetscMax(maxlen,(ai[i+1] - ai[i]));
    for (j=0; j<bs; j++) {
      rowlengths[i*bs+j] = bs*(ai[i+1] - ai[i]);
    }
  }
  ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,A->m,A->n,0,rowlengths,B);CHKERRQ(ierr);
  ierr = MatSetOption(*B,MAT_COLUMN_ORIENTED);CHKERRQ(ierr);
  ierr = MatSetOption(*B,MAT_ROWS_SORTED);CHKERRQ(ierr);
  ierr = MatSetOption(*B,MAT_COLUMNS_SORTED);CHKERRQ(ierr);
  ierr = PetscFree(rowlengths);CHKERRQ(ierr);

  ierr = PetscMalloc(bs*sizeof(int),&rows);CHKERRQ(ierr);
  ierr = PetscMalloc(bs*maxlen*sizeof(int),&cols);CHKERRQ(ierr);
  for (i=0; i<n; i++) {
    for (j=0; j<bs; j++) {
      rows[j] = i*bs+j;
    }
    ncols = ai[i+1] - ai[i];
    for (k=0; k<ncols; k++) {
      for (j=0; j<bs; j++) {
        cols[k*bs+j] = bs*(*aj) + j;
      }
      aj++;
    }
    ierr  = MatSetValues(*B,bs,rows,bs*ncols,cols,aa,INSERT_VALUES);CHKERRQ(ierr);
    aa   += ncols*bs*bs;
  }
  ierr = PetscFree(cols);CHKERRQ(ierr);
  ierr = PetscFree(rows);CHKERRQ(ierr);
  ierr = MatAssemblyBegin(*B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  ierr = MatAssemblyEnd(*B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}
EXTERN_C_END