partitioners.h

// Copyright (C) 2020-2026 Garth N. Wells and Igor A. Baratta
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
// SPDX-License-Identifier:    LGPL-3.0-or-later
 
#pragma once
 
#include "partition.h"
#include <array>
#include <optional>
#include <span>
 
namespace dolfinx::graph
{

template <typename T>
graph::AdjacencyList<int> compute_destination_ranks(
    MPI_Comm comm, const graph::AdjacencyList<std::int64_t>& graph,
    const std::vector<T>& node_disp, const std::vector<T>& part);
 
namespace scotch
{
#ifdef HAS_PTSCOTCH
enum class strategy : std::uint8_t
{
  none,
  balance,
  quality,
  safety,
  speed,
  scalability
};

graph::partition_fn partitioner(scotch::strategy strategy = strategy::speed,
                                double imbalance = 0.025, int seed = 0);
#endif
 
} // namespace scotch
 
namespace parmetis
{
#ifdef HAS_PARMETIS
graph::partition_fn partitioner(double imbalance = 1.02,
                                std::array<int, 3> options = {1, 0, 5});

graph::partition_fn repartitioner(double ipc2redist = 1000.0,
                                  double imbalance = 1.02,
                                  std::array<int, 3> options = {1, 0, 5});

std::vector<int>
geom_partitioner(MPI_Comm comm, int nparts, std::span<const double> x, int gdim,
                 std::optional<std::span<const std::int32_t>> node_weights);

graph::hybrid_partition_fn geom_partitioner_kway(double imbalance = 1.02,
                                                 std::array<int, 3> options
                                                 = {1, 0, 5});
#endif
} // namespace parmetis

namespace kahip
{
#ifdef HAS_KAHIP
graph::partition_fn partitioner(int mode = 1, int seed = 1,
                                double imbalance = 0.03,
                                bool suppress_output = true);
#endif
} // namespace kahip
 
} // namespace dolfinx::graph