#graph-algorithms #nauty

sys nauty-Traces-sys

Low-level bindings for nauty and Traces

10 releases (6 breaking)

0.7.0 Nov 21, 2023
0.6.1 Jul 21, 2023
0.6.0 May 6, 2023
0.5.0 Mar 25, 2023
0.1.1 May 27, 2020

#86 in Math

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Used in 5 crates (4 directly)


26K SLoC

C 25K SLoC // 0.1% comments Rust 1K SLoC // 0.1% comments

Low-level bindings for nauty and Traces

This crate provides ffi bindings for nauty and Traces. Nauty and Traces are implementations of algorithms for computing graph automorphisms.


Add the following lines to your Cargo.toml:

nauty-Traces-sys = "0.7"

By default, you need a C compiler installed on your system. See the Features section for alternatives.


  • You can use either the version of nauty and Traces that is bundled with this crate or a local installation. Both options have advantages and disadvantages. See the Features section below. Note that version 0.7 of this crate assumes nauty & Traces version 2.8.8 and may not work with other versions.

  • Some C macros have no direct equivalent.

    • Instead of using DYNALLSTAT and DYNALLOC you can create Vecs or arrays.

    • Most DEFAULT-type macros have been replaced with implementations of the rust Default trait.

    • The following macros are implemented as functions:

      Original macro Replacement
      EMPTY_GRAPH empty_graph
      DEFAULTOPTIONS_SPARSEGRAPH optionsblk::default_sparse()
      DEFAULTOPTIONS_DIGRAPH optionsblk::default_digraph()
      DEFAULTOPTIONS_SPARSEDIGRAPH optionsblk::default_sparse_digraph()
    • The SparseGraph struct helps with creating sparse graphs. A &mut SparseGraph can be converted to the sparsegraph used by nauty and Traces.


The following program prints the generators for the automorphism groups of n-vertex polygons. It is a pretty literal translation of the nautyex2 C program that is part of the nauty and Traces bundle.

use nauty_Traces_sys::*;
use std::io::{self, Write};
use std::os::raw::c_int;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut options = optionblk::default();
    options.writeautoms = TRUE;
    let mut stats = statsblk::default();

    loop {
        print!("\nenter n : ");
        let mut input = String::new();
        io::stdin().read_line(&mut input)?;
        let n = input.trim().parse()?;
        if n > 0 {

            let m = SETWORDSNEEDED(n);

            unsafe {
                nauty_check(WORDSIZE as c_int, m as c_int, n as c_int, NAUTYVERSIONID as c_int);

            let mut lab = vec![0; n];
            let mut ptn = vec![0; n];
            let mut orbits = vec![0; n];

            let mut g = empty_graph(m, n);
            for v in 0..n {
                ADDONEEDGE(&mut g, v, (v + 1) % n, m);

            println!("Generators for Aut(C[{}]):", n);

            unsafe {
                    &mut options,
                    &mut stats,
                    m as c_int,
                    n as c_int,

            for orbit in orbits {
                print!("{} ", orbit)

            print!("order = ");
            unsafe {
                writegroupsize(stderr, stats.grpsize1, stats.grpsize2);
        } else {


See The Cargo Book for guidance on features.

Default features

  • bundled: Use the version of nauty and Traces that comes bundled with this crate. This requires a C compiler on your system.

    Deactivate this feature to use a custom installation. In that case, you can only free memory allocated by nauty and Traces if this crate is linked to the same libc. Use the libc feature to generate the required bindings.

  • tls: Ensure thread-safety in the bundled library. Corresponds to compiling nauty and Traces with USE_TLS defined.

  • libc: nauty and Traces sometimes allocate memory internally, for example in the nauty_to_sg function. This feature enable bindings to DYNFREE and SG_FREE, which are needed to deallocate this memory again. Note that this can only be done safely if nauty and Traces are linked to the same libc as this crate.

Non-default features

Activating the following features may make the generated binaries faster but less portable.

  • clz: Allow using the lzcnt processor instruction, if available.

  • popcnt: Allow using the popcnt processor instruction, if available.

  • native: Allow processor instructions that are specific to the current hardware. Implies clz and popcnt.

License: Apache-2.0


~41K SLoC