pymetis 2025.2.2

A graph partitioning package

PyMetis is a Python wrapper for the Metis graph partitioning software by George Karypis, Vipin Kumar and others. It includes version 5.1.0 of Metis and wraps it using the Pybind11 wrapper generator library. So far, it only wraps the most basic graph partitioning functionality (which is enough for my current use), but extending it in case you need more should be quite straightforward. Using PyMetis to partition your meshes is really easy–essentially all you need to pass into PyMetis is an adjacency list for the graph and the number of parts you would like.

Links

• Documentation (read how things work)

• Conda Forge (download binary packages for Linux, macOS, Windows)

• Python package index (download releases)

• C. Gohlke’s Windows binaries (download Windows binaries)

• Github (get latest source code, file bugs)

Installation

The following line should do the job:

pip install pymetis

Quick Start

This graph, adapted from Figure 2 of the Metis manual to use zero-based indexing,

can be defined and partitioned into two graphs with

import numpy as np
import pymetis
adjacency_list = [np.array([4, 2, 1]),
                  np.array([0, 2, 3]),
                  np.array([4, 3, 1, 0]),
                  np.array([1, 2, 5, 6]),
                  np.array([0, 2, 5]),
                  np.array([4, 3, 6]),
                  np.array([5, 3])]
n_cuts, membership = pymetis.part_graph(2, adjacency=adjacency_list)
# n_cuts = 3
# membership = [1, 1, 1, 0, 1, 0, 0]

nodes_part_0 = np.argwhere(np.array(membership) == 0).ravel() # [3, 5, 6]
nodes_part_1 = np.argwhere(np.array(membership) == 1).ravel() # [0, 1, 2, 4]