cograph-generator 0.1.1

A high-performance Python library for generating and manipulating cographs, with canonical structure parsing and graph6 encoding.

CographGenerator

CographGenerator is a high-performance Python library for generating and manipulating cographs, with canonical structure parsing and Graph6 encoding. The library focuses on generating all cographs of a given size and exporting them in graph6 (g6) format, suitable for graph-theoretical applications and combinatorial research.

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Installation

You can install the library via pip:

pip install cographgenerator

Note: This library depends on NumPy, which will be installed automatically.

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Quick Start

The main function exposed by the library is generate_cographs_final_g6, which generates all cographs for a given number of vertices and saves them to a file in graph6 format.

from cographgenerator import generate_cographs_final_g6

Generate all cographs with 3 vertices

output_file = generate_cographs_final_g6(node_count=3, output_filename="cographs_3.g6")

print(f"Cographs generated and saved in: {output_file}")

This will create a file named cographs_3.g6 containing all canonical cographs with 3 vertices encoded in graph6 format.

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Parameters

Parameter	Type	Default	Description
node_count	int	—	Number of vertices in the cographs to generate.
output_filename	str	"cographs_g6.txt"	Destination filename for the final graph6 output.
batch_size	int	50000	Number of structures to convert per batch in phase 2.
num_processes	int	8	Number of worker processes used during graph6 conversion.

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How it Works

1. Generate canonical cotree structures: Recursively constructs all canonical string representations of cographs of a given size.
2. Convert structures to adjacency matrices: Each canonical structure is converted into a square adjacency matrix.
3. Encode in Graph6 format: The adjacency matrices are transformed into compact graph6 strings and written to the output file.

The library internally optimizes memory usage by streaming the structures and processing them in batches, making it suitable for large graphs.

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License

This project is licensed under the MIT License.

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References

• Graph6 Format: https://users.cecs.anu.edu.au/~bdm/nauty/manual.pdf
• Cographs on Wikipedia: https://en.wikipedia.org/wiki/Cograph