passagemath-plantri

10.8.4 verified Sat May 09 auth: no python

A Python interface to plantri and fullgen for generating planar triangulations, cubic planar graphs, and other planar graph families. Part of the passagemath ecosystem. Current version 10.8.4, requires Python 3.11-3.14. Releases follow passagemath release cycle.

pip install passagemath-plantri

Common errors

error RuntimeError: plantri binary not found ↓

cause The plantri/fullgen executable is not installed or not in PATH.

fix

Install plantri system-wide (e.g., 'apt install plantri' or download from official site and add to PATH). Verify by typing 'plantri' in terminal.

error ImportError: No module named 'passagemath.plantri' ↓

cause Missing passagemath-plantri installation or wrong import statement.

fix

Run 'pip install passagemath-plantri' and import as 'from passagemath.plantri import ...'.

error ValueError: n must be at least ... ↓

cause Minimum vertex count constraints vary by graph family (e.g., planar triangulations require n>=4).

fix

Check documentation for minimum n; for planar_triangulations start at n>=4.

Warnings

gotcha The `plantri` and `fullgen` binaries must be installed separately (e.g., via system package manager or by downloading from plantri website) and placed in PATH. Wrapper does NOT bundle them. ↓

fix Install plantri binary (e.g., 'sudo apt install plantri' on Debian/Ubuntu, or download from https://users.cecs.anu.edu.au/~bdm/plantri/)

deprecated Passing integer arguments directly to plantri functions (e.g., planar_triangulations(6)) is deprecated. Use PlantriOptions class instead. ↓

fix Use PlantriOptions(n=6, ...) and pass to functions

breaking Before passagemath 10.0, the library was named 'plantri' on PyPI and imported as 'import plantri'. Now it's 'passagemath-plantri' and imported from passagemath.plantri. ↓

fix Update imports: from passagemath.plantri import ...

gotcha Generated graphs are passagemath Graph objects, not networkx or igraph. Use .graph6_string() or adjacency_matrix() to convert. ↓

fix Use methods like g.graph6_string() or g.to_networkx() if passagemath-networkx installed

Imports

planar_triangulations
wrong
```
import plantri
```
correct
```
from passagemath.plantri import planar_triangulations
```
The library is a submodule of passagemath, not a standalone package

PlantriOptions

from passagemath.plantri import PlantriOptions

Quickstart

Generate all planar triangulations on 6 vertices (2 connected, 3-connected) and print each as graph6 string.

from passagemath.plantri import planar_triangulations
for g in planar_triangulations(6):
    print(g.graph6_string())