vw-executor 0.3.3

Helpers for driving vw execution from python

What is this?

Python helper for running vowpalwabbit on multiple command line arguments and have programmatic access to results.

Getting started

Initialize the wrapper

from vw_executor.vw import Vw
vw = Vw(
    'path to cache folder',
    'path to vw binary'         # Optional. If empty, pyvw is used
    )

Run on single configuration

result = vw.train(INPUTS, CONFIGURATION)

where

INPUTS - list of paths to input files

CONFIGURATION

Every configuration can be defined using one of the following ways:

1. string. I.e.

result = vw.train(['input1.txt'], '--cb_explore_adf --dsjson')

2. dictionary. In this case, for every key/value pair:

• If value is None/NaN the whole pair is skipped
• If key starts with '#', key is skipped
• Otherwise f'{key} {value}' is added to command line

For example,

vw.train(['input1.txt'], {'#base': '--cb_explore_adf --dsjson', '--epsilon': 0.2, '--learning_rate': None})

is running vw binary with the following command line:

--cb_explore_adf --dsjson --epsilon 0.2

Run on multiple configurations

result = vw.train(INPUTS, CONFIGURATIONS)

CONFIGURATIONS is the list of CONFIGURATION here. It is recommended to use helper vw_opts.Grid class in order to create it. Grid can be constructed using one of the following ways:

1. From Iterable of CONFIGURATION. For example,

from vw_executor.vw_opts import Grid
vw.train(['input1.txt'], Grid(['--cb_explore_adf --dsjson -l 0.1', '--cb_explore_adf --dsjson -l 0.2']))

2. From dictionary with string keys and iterable values.
   1. Grid({'-k': ['v1', 'v2']}) is equivalent to Grid(['-k v1', '-k v2'])
   2. Grid({'-k1': [v1, v2], '-k2': [v3, v4]}) is equivalent to Grid(['-k1 v1 -k2 v3', '-k1 v1 -k2 v4', '-k1 v2 -k2 v3', '-k1 v2 -k2 v4'])

Grid supports multiplication("and") and summation("or") operators. For example,

Grid({
    '-k1': ['v1, v2']
}) * (Grid({'-k2': ['v3']}) + Grid({'-k3': ['v4']}))

is equivalent to

Grid(['-k1 v1 -k2 v3', '-k1 v1 -k3 v4', '-k1 v2 -k2 v3', '-k1 v2 -k3 v4'])