🌲 PhyloDM

PhyloDM is a high-performance library that converts a phylogenetic tree into a pairwise distance matrix.

For a tree with 30,000 taxa, PhyloDM will use:

• ~14GB of memory (94% less than DendroPy)
• ~1 minute of CPU time (183x faster than DendroPy).

PhyloDM is written in Rust and is exposed to Python via the Python PyO3 API. This means it can be used in either Python or Rust, however, the documentation below is written for use in Python. For Rust documentation, see Crates.io.

⚙ Installation

Requires Python 3.7+

PyPI

Pre-compiled binaries are packaged for most 64-bit Unix platforms. If you are installing on a different platform then you will need to have Rust installed to compile the binaries.

shell python -m pip install phylodm

Conda

shell conda install -c b bioconda phylodm

🐍 Quick-start

A pairwise distance matrix can be created from either a Newick file, or DendroPy tree.

```python from phylodm import PhyloDM

PREPARATION: Create a test tree

with open('/tmp/newick.tree', 'w') as fh: fh.write('(A:4,(B:3,C:4):1);')

1a. From a Newick file

pdm = PhyloDM.loadfromnewick_path('/tmp/newick.tree')

1b. From a DendroPy tree

import dendropy tree = dendropy.Tree.getfrompath('/tmp/newick.tree', schema='newick') pdm = PhyloDM.loadfromdendropy(tree)

2. Calculate the PDM

dm = pdm.dm(norm=False) labels = pdm.taxa()

""" /------------[4]------------ A + | /---------[3]--------- B ---[1]---+ ------------[4]------------- C

labels = ('A', 'B', 'C') dm = [[0. 8. 9.] [8. 0. 7.] [9. 7. 0.]] """ ```

Accessing data

The dm method generates a symmetrical NumPy matrix and returns a tuple of keys in the matrix row/column order.

```python

Calculate the PDM

dm = pdm.dm(norm=False) labels = pdm.taxa()

""" /------------[4]------------ A + | /---------[3]--------- B ---[1]---+ ------------[4]------------- C

labels = ('A', 'B', 'C') dm = [[0. 8. 9.] [8. 0. 7.] [9. 7. 0.]] """

e.g. The following commands (equivalent) get the distance between A and B

dm[0, 1] # 8 dm[labels.index('A'), labels.index('B')] # 8 ```

Normalisation

If the norm argument of dm is set to True, then the data will be normalised by the sum of all edges in the tree.

⏱ Performance

Tests were executed using scripts/performance/Snakefile on an Intel(R) Xeon(R) CPU E5-2650 v3 @ 2.30GHz.

For large numbers of taxa it is beneficial to use PhyloDM, however, if you have a small number of taxa in the tree it is beneficial to use DendroPy for the great features it provides.