passagemath-bliss

10.8.4 verified Fri May 01 auth: no python

A Python binding for the bliss graph isomorphism library, part of the passagemath ecosystem. It provides efficient automorphism group computation and (sub)graph isomorphism. Version 10.8.4 requires Python <3.15,>=3.11.

pip install passagemath-bliss

Common errors

error ImportError: cannot import name 'bliss' from 'sage.graphs' ↓

cause Using wrong import path or missing passagemath packages.

fix

Install passagemath-sage and use from sage.graphs.bliss import canonical_form.

error ValueError: graph must be simple (no loops or multiple edges) ↓

cause Bliss only supports simple graphs.

fix

Use G.to_simple() before passing to bliss functions.

Warnings

deprecated The standalone `bliss` module (e.g., `from bliss import *`) is deprecated. Use `sage.graphs.bliss` instead. ↓

fix Change imports to `from sage.graphs.bliss import ...`.

gotcha Not all bliss functions accept multigraphs; edges with multiple parallel edges may cause silent failures. ↓

fix Convert multigraphs to simple graphs before calling bliss functions.

Imports

bliss
wrong
```
import bliss
```
correct
```
from sage.graphs.bliss import *
```
bliss is accessed through sage.graphs, not as a top-level module.

canonical_form

from sage.graphs.bliss import canonical_form

Quickstart

Compute canonical form and automorphism group of a graph using bliss.

from sage.graphs.bliss import canonical_form, automorphism_group
g = graphs.PetersenGraph()
canon, relabel = canonical_form(g, return_relabeling=True)
print(canon.edges()[:2])
aut = automorphism_group(g)
print(aut.order())