Actual source code: shellcnv.c

  1: /*$Id: shellcnv.c,v 1.20 2001/08/07 03:02:51 balay Exp $*/

 3:  #include src/mat/matimpl.h
 4:  #include vecimpl.h
  5: 
  8: int MatConvert_Shell(Mat oldmat,const MatType newtype,Mat *newmat) {
  9:   Mat           mat;
 10:   Vec           in,out;
 11:   int           ierr,i,M,m,*rows,start,end;
 12:   MPI_Comm      comm;
 13:   PetscScalar   *array,zero = 0.0,one = 1.0;

 16:   comm = oldmat->comm;

 18:   MatGetOwnershipRange(oldmat,&start,&end);
 19:   VecCreateMPI(comm,end-start,PETSC_DECIDE,&in);
 20:   VecDuplicate(in,&out);
 21:   VecGetSize(in,&M);
 22:   VecGetLocalSize(in,&m);
 23:   PetscMalloc((m+1)*sizeof(int),&rows);
 24:   for (i=0; i<m; i++) {rows[i] = start + i;}

 26:   MatCreate(comm,m,M,M,M,&mat);
 27:   MatSetType(mat,newtype);

 29:   for (i=0; i<M; i++) {
 30:     VecSet(&zero,in);
 31:     VecSetValues(in,1,&i,&one,INSERT_VALUES);
 32:     VecAssemblyBegin(in);
 33:     VecAssemblyEnd(in);

 35:     MatMult(oldmat,in,out);
 36: 
 37:     VecGetArray(out,&array);
 38:     MatSetValues(mat,m,rows,1,&i,array,INSERT_VALUES);
 39:     VecRestoreArray(out,&array);

 41:   }
 42:   PetscFree(rows);
 43:   VecDestroy(in);
 44:   VecDestroy(out);
 45:   MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);
 46:   MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);

 48:   /* Fake support for "inplace" convert. */
 49:   if (*newmat == oldmat) {
 50:     MatDestroy(oldmat);
 51:   }
 52:   *newmat = mat;
 53:   return(0);
 54: }