README.md

cvanmf

An implementation of bicrossvalidation for Non-negative Matrix Factorisation (NMF) rank selection, along with methods for analysis and visualisation of NMF decomposition.

For details on the method, please see:

• Enterosignatures define common bacterial guilds in the human gut microbiome, Frioux, Clémence et al., Cell Host & Microbe, Volume 31, Issue 7, 1111 - 1125.e6 (https://doi.org/10.1016/j.chom.2023.05.024)

Documentation

Documentation can be found at readthedocs.

Overview

NMF is an unsupervised machine learning techniques which provides a representation of a numeric input matrix $X$ as a mixture of $k$ of underlying parts. In this package we refer to each of these parts as a signature. Each signature can be described by how much each feature contributes to it. For example, we can represent the abundance of bacteria in the human gut as a mixture of 5 signatures.

The number of signatures (or rank, $k$) has to specified when performing NMF, and selecting an appropriate value for $k$ is an important step. We implement bicrossvalidation with Gabriel style holdouts. Broadly speaking, this method holds out one block of the matrix ($A$) and makes an estimate of it ($A'$) using the remainder of the matrix. How closely $A'$ resembles $A$ is used to identify and appropriate rank.

Input

Any numeric matrix can be used as input, with samples on columns, and features on rows. Each row should describe something similar, e.g. each is the abundance of a microbe, or abundance of a transcript. A minimum of 2 samples is required. When number of samples $n$ is close to the number of signatures $k$, signatures are likely to represent individual samples rather than broad patterns.

References

If you use this tool please cite: For details on the method, please see:

• Enterosignatures define common bacterial guilds in the human gut microbiome, Frioux, Clémence et al., Cell Host & Microbe, Volume 31, Issue 7, 1111 - 1125.e6 (https://doi.org/10.1016/j.chom.2023.05.024)

For background on NMF, see: For background on NMF see:

• Lee & Seung, 1999 (https://doi.org/10.1038/44565) for the paper introducing NMF
• Jiang et al, 2012 (https://doi.org/10.1007/s00285-011-0428-2) for a good description of the method and application to metagenomic data