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Description:

meco 1.0.1

The MECO (Multi-objective Evolutionary
COmpression) algorithm is a tool to perform:

dataset compression,
feature selection, and
coreset discovery.

This python package provides a sklearn-like transformer
implementation of the MECO algorithm.

Quick start
You can install the meco package along with all its dependencies from
PyPI:
$ pip install meco

Example
For this simple experiment, let’s use the digits
dataset from sklearn. We first need to import the dataset,
a simple sklearn classifier (e.g. Ridge) and the MECO transformer.
We can then load the dataset, create a MECO model, and
fit the model on the digits dataset:
from sklearn.datasets import load_digits
from sklearn.linear_model import RidgeClassifier

from meco import MECO

X, y = load_digits(return_X_y=True)

model = MECO(RidgeClassifier(random_state=42))
model.fit(X, y)
Once training is over, we get a view of the compressed
input data X containing the most relevant samples
(i.e. a subset of the rows in X, a.k.a. the coreset),
and the most relevant features (i.e. a subset of the columns in X):
x_reduced = model.transform(X)
Once trained, the model.best_set_ dictionary contains:

the indices of the most relevant samples,
the indices of the most relevant features, and
the validation accuracy of the compressed dataset x_reduced, e.g.:

>>> model.best_set_
{
'samples': [0, 2, 4, ...],
'features': [3, 7, 8, ...],
'accuracy': 0.9219,
}
The compressed dataset (x_reduced, y_reduced) can be used
instead of the original dataset (X, y) to train machine
learning models more efficiently:
from sklearn.ensemble import RandomForestClassifier

y_reduced = y[model.best_set_['samples']]

classifier = RandomForestClassifier(random_state=42)
classifier.fit(x_reduced, y_reduced)

Tasks

Dataset compression
Should you need to compress the whole dataset X
(i.e. for dataset compression), you can set the parameter compression
to 'both' (this is the default behaviour anyway):
model = MECO(RidgeClassifier(), compression='both')

Coreset discovery
Should you need to compress the rows of X only
(i.e. for coreset discovery), you can set the parameter compression
to 'samples':
model = MECO(RidgeClassifier(), compression='samples')

Feature selection
Should you need to compress the columns of X only
(i.e. for feature selection), you can set the parameter compression
to 'features':
model = MECO(RidgeClassifier(), compression='features')

Citing
If you find MECO useful in your research, please consider citing the following papers:
@inproceedings{barbiero2019novel,
title={A Novel Outlook on Feature Selection as a Multi-objective Problem},
author={Barbiero, Pietro and Lutton, Evelyne and Squillero, Giovanni and Tonda, Alberto},
booktitle={International Conference on Artificial Evolution (Evolution Artificielle)},
pages={68--81},
year={2019},
organization={Springer}
}

@article{barbiero2020uncovering,
title={Uncovering Coresets for Classification With Multi-Objective Evolutionary Algorithms},
author={Barbiero, Pietro and Squillero, Giovanni and Tonda, Alberto},
journal={arXiv preprint arXiv:2002.08645},
year={2020}
}

Source
The source code and minimal working examples can be found on
GitHub.

Authors
Pietro Barbiero,
Giovanni Squillero,
and
Alberto Tonda.

Licence
Copyright 2020 Pietro Barbiero, Giovanni Squillero, and Alberto Tonda.
Licensed under the Apache License, Version 2.0 (the “License”); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0.
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an “AS IS” BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.