spherogram

library2.4.1pypypi✓ verified 84d ago

A Python library for spherical diagrams in 3-manifold topology, including links, knots, braids, tangles, and planar diagrams. Current version 2.4.1 supports ribbon concordance tools, bridge number bounds, and knot Floer homology. Release cadence is irregular, with major features in even-numbered versions.

data ai-ml

pip install spherogram

github ↗package ↗

INSTALL

IMPORT

SIG · SPHEROGRAM

spherogram

datapythonv2.4.1

Install

4.3s avg

Import

676ms

Disk

169MB

Pass rate

5/ 10

Env Coverage5 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v2.4.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

build_error

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 4.3s · import 0.676s · 169MB

169MB installed

● package 169MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Link

✓ from spherogram import Link

✗ from spherogram.links import Link

Top-level import is correct; submodule imports may break

Knot

✓ from spherogram import Knot

Tangle

✓ from spherogram import Tangle

✗ from spherogram.tangles import Tangle

Submodule path may not be stable

Creates a link from a named knot (e.g. 'K11n34') and computes its bridge number and Jones polynomial.

from spherogram import Link L = Link('K11n34') print(L.bridge_number()) print(L.jones_polynomial())

Debug

Known issues

breakingVersion 2.0 changed the sign convention for knot signature (positive knots now have negative signature) and braid generator signs (positive generators give positive crossings). Older code expecting old signs will produce wrong results.

fix

Update any code relying on signature signs or braid generator orientation.

affects: >=2.0

breakingThe function `Link.simplify()` was significantly improved in 2.1 but may change the diagram representation; do not depend on stable crossing order after simplification.

fix

Do not assume crossing indices or ordering remain constant after simplify().

affects: >=2.1

deprecatedAutomatic import of `snappy_16_knots` in 2.4.1 may be removed in future; always import explicitly if needed.

fix

Use `from snappy_16_knots import ...` explicitly.

affects: 2.4.1+

gotchaMany functions return `Link` objects that may have duplicate crossings or be non-minimal; always call `simplify()` before computing invariants if diagram size matters.

fix

After constructing a Link, call L.simplify() for a reduced diagram.

affects: all

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'spherogram'

spherogram not installed or installed in wrong environment.

fix

Run `pip install spherogram` in the target Python environment.

ImportError: cannot import name 'Link' from 'spherogram.links'

Using incorrect submodule import path. The correct symbol is at top level.

fix

Change to `from spherogram import Link`.

ValueError: Unrecognized knot name

Knot name not in the internal database or string malformed.

fix

Use standard notation like 'K11n34' (K = knot, 11 crossings, n = non-alternating, 34th in table). Check spherogram's knot_table for available names.

Upgrade

Version history

2.4.1latest on PyPI · released Feb 9, 2026

Audit

Dependencies

snappyrequiredRequired for snapPy integration and auto-import of snappy_16_knots

Agent activity

13 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/3-manifolds/Spherogram ↗

packagehttps://pypi.org/project/spherogram/ ↗