hasse

Python library for representing Partially Ordered sets via Hasse Diagrams.

Table of Contents

• Installation
• Usage

Installation

If you just need to use hasse, you can just run:

$ pip install hasse

For developers, note that this project uses the poetry python package/dependency management tool. Please familarize yourself with it and then run:

$ poetry install

Usage

hasse is centered around the hasse.PoSet class. An example is given below.

import hasse

poset = hasse.PoSet.from_chains(
    [1, 2, 4],  # 1 < 2 < 4
    [1, 3, 4],  # 1 < 3 < 4
)

# Test membership and size.
assert 2 in poset
assert len(poset) == 4
assert set(poset) == {1,2,3,4}

# Perform pair wise comparison.
assert poset.compare(1, 1) == '='
assert poset.compare(1, 4) == '<'
assert poset.compare(4, 2) == '>'
assert poset.compare(2, 3) == '||'

# Add an edge.
poset2 = poset.add([2, 1])
poset2.compare(1, 2) == '='

PoSet must be a DAG. For large posets we encourage batching via from_chains over many small add() calls.