database-knotinfo 2021.7.21

The KnotInfo and LinkInfo databases as lists of dictionaries

Database KnotInfo

This repository contains a snapshot of the complete content of the KnotInfo and LinkInfo databases. Each database is provided as a Python list of Python dictionaries. The data are from the corresponding Excel spreadsheets available on the KnotInfo and LinkInfo homepages on the date of release.

This repository was created as a part of the SageMath interface to these databases (see Sage Trac ticket #30352) but can also be used independently.

In Python, it can be used as follows:

>>> from database_knotinfo import link_list
>>> k = link_list()
>>> len(k)
2979
>>> names_k = k[0]
>>> type(names_k)
<type 'dict'>
>>> names_k['braid_index']
'Braid Index'
>>> k2 = k[2]
>>> k2['name']
'3_1'
>>> k2['braid_index']
'2'
>>> k2['homfly_polynomial']
'(2*v^2-v^4)+(v^2)*z^2'

>>> l = link_list(proper_links=True)
>>> len(l)
4189
>>> names_l = l[0]
>>> type(names_l)
<type 'dict'>
>>> names_l['braid_notation']
'Braid Notation'
>>> l2 = l[2]
>>> l2['name']
'L2a1{1}'
>>> l2['homflypt_polynomial']
'v/z-v^3/z + v*z'

To build a new release, the CSV files can be upgraded with the create_knotinfo_csv.py script. A cronjob executes it on the first day of every month and creates a new release if differences are detected.

Installation

Python

pip install database_knotinfo

SageMath

Once ticket #30352 is released, the database can be installed in Sage by:

sage -i database_knotinfo

This will contain integration with the knot and link functionality of Sage. Of course the flat Python functionality is already available by:

sage -pip install database_knotinfo

Versioning

Version numbers are automatically generated every month if differences to the original databases are detected. They follow the scheme

<year>.<month>.<day>

Help

If you note a divergence between this repository and the original data in case the current release is older than a month please create an issue about that.

Credits

Many thanks to Chuck Livingston and Allison Moore for making the data available. For further acknowledgments see the corresponding homepages.