GraphHelper_Scotch(const CrsMatrixType& A,
const int seed = GraphHelper::DefaultRandomSeed) {
_label = "GraphHelper_Scotch::" + A.Label();
_is_ordered = false;
_cblk = 0;
// scotch does not allow self-contribution (diagonal term in sparse matrix)
_base = 0; //A.BaseVal();
_m = A.NumRows();
_nnz = A.NumNonZeros();
_rptr = size_type_array(_label+"::RowPtrArray", _m+1);
_cidx = ordinal_type_array(_label+"::ColIndexArray", _nnz);
_perm = ordinal_type_array(_label+"::PermutationArray", _m);
_peri = ordinal_type_array(_label+"::InvPermutationArray", _m);
_range = ordinal_type_array(_label+"::RangeArray", _m);
_tree = ordinal_type_array(_label+"::TreeArray", _m);
// create a graph structure without diagonals
A.convertGraph(_nnz, _rptr, _cidx);
int ierr = 0;
ordinal_type *rptr = reinterpret_cast<ordinal_type*>(_rptr.ptr_on_device());
ordinal_type *cidx = reinterpret_cast<ordinal_type*>(_cidx.ptr_on_device());
if (seed != GraphHelper::DefaultRandomSeed) {
SCOTCH_randomSeed(seed);
SCOTCH_randomReset();
}
ierr = SCOTCH_graphInit(&_graph);
CHKERR(ierr);
ierr = SCOTCH_graphBuild(&_graph, // scotch graph
_base, // base value
_m, // # of vertices
rptr, // column index array pointer begin
rptr+1, // column index array pointer end
NULL, // weights on vertices (optional)
NULL, // label array on vertices (optional)
_nnz, // # of nonzeros
cidx, // column index array
NULL);
CHKERR(ierr); // edge load array (optional)
ierr = SCOTCH_graphCheck(&_graph);
CHKERR(ierr);
}
