thomas-core 0.1.0a2

Thomas, a library for working with Bayesian Networks.

Thomas

Very simple (almost naive ;-) bayesian network implementation.

Example (module thomas.core.examples) contains examples from the book "Probabilistic Graphical Models: Principles and Techniques" from Koller and Friedman (PGM Stanford) and from the lecture by Adnan Darwiche on YouTube:

• 6a. Inference by Variable Elimination I (Chapter 6).
• 6b. Inference by Variable Elimination II (Chapter 6).

Installation

Normal

To install from PyPI use pip:

$ pip install thomas-core

Development

To do a development install:

$ git clone https://github.com/mellesies/thomas-core
$ cd thomas-core
$ pip install -e .

Usage

To get started with querying a network, try the following:

from thomas.core import examples

# Load an example network
Gs = examples.get_student_network()

# This should output the prior probability of random variable 'S' (SAT score).
print(Gs.P('S'))
print()

# Expected output:
# P(S)
# S
# s0    0.725
# s1    0.275
# dtype: float64

# Query for the conditional probability of S given the student is intelligent.
print(Gs.P('S|I=i1'))

# Expected output:
# P(S)
# S
# s0    0.2
# s1    0.8
# dtype: float64

Alternatively, you can have a go at the example notebooks through Binder:

• notebooks/1. Factors.ipynb
• notebooks/2. Bags of factors.ipynb
• notebooks/3. Conditional probability tables.ipynb
• notebooks/4. Bayesian Networks.ipynb