EXTERN_C_BEGIN
/*
MatOrdering_ND - Find the nested dissection ordering of a given matrix.
*/
#undef __FUNCT__
#define __FUNCT__ "MatOrdering_ND"
PetscErrorCode PETSCMAT_DLLEXPORT MatOrdering_ND(Mat mat,const MatOrderingType type,IS *row,IS *col)
{
PetscErrorCode ierr;
PetscInt i, *mask,*xls,*ls,nrow,*ia,*ja,*perm;
PetscTruth done;
PetscFunctionBegin;
ierr = MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);CHKERRQ(ierr);
if (!done) SETERRQ1(PETSC_ERR_SUP,"Cannot get rows for matrix type %s",((PetscObject)mat)->type_name);
ierr = PetscMalloc4(nrow,PetscInt,&mask,nrow,PetscInt,&perm,nrow+1,PetscInt,&xls,nrow,PetscInt,&ls);CHKERRQ(ierr);
SPARSEPACKgennd(&nrow,ia,ja,mask,perm,xls,ls);
ierr = MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);CHKERRQ(ierr);
/* shift because Sparsepack indices start at one */
for (i=0; i<nrow; i++) perm[i]--;
ierr = ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);CHKERRQ(ierr);
ierr = ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);CHKERRQ(ierr);
ierr = PetscFree4(mask,perm,xls,ls);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*
MatGetOrdering_ND - Find the nested dissection ordering of a given matrix.
*/
PETSC_INTERN PetscErrorCode MatGetOrdering_ND(Mat mat,MatOrderingType type,IS *row,IS *col)
{
PetscErrorCode ierr;
PetscInt i, *mask,*xls,*ls,nrow,*perm;
const PetscInt *ia,*ja;
PetscBool done;
PetscFunctionBegin;
ierr = MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);CHKERRQ(ierr);
if (!done) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Cannot get rows for matrix type %s",((PetscObject)mat)->type_name);
ierr = PetscMalloc4(nrow,&mask,nrow,&perm,nrow+1,&xls,nrow,&ls);CHKERRQ(ierr);
SPARSEPACKgennd(&nrow,ia,ja,mask,perm,xls,ls);
ierr = MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,NULL,&ia,&ja,&done);CHKERRQ(ierr);
/* shift because Sparsepack indices start at one */
for (i=0; i<nrow; i++) perm[i]--;
ierr = ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,row);CHKERRQ(ierr);
ierr = ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,col);CHKERRQ(ierr);
ierr = PetscFree4(mask,perm,xls,ls);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
