omesa 0.2.7a0

Omesa
=====

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.. _scikit-learn: http://scikit-learn.org/stable/
.. _readthedocs: http://omesa.readthedocs.org/

A small framework for reproducible Text Mining research that largely builds
on top of scikit-learn_. Its goal is to make common research procedures fully
automated, optimized, and well recorded. To this end it features:

- Exhaustive search over best features, pipeline options, to classifier optimization.
- Flexible wrappers to plug in your tools and features of choice.
- Completely sparse pipeline through hashing - from data to feature space.
- Record of all settings and fitted parts of the entire experiment, promoting reproducibility.
- Dump an easily deployable version of the final model for plug-and-play demos.

Read the documentation at readthedocs_.

.. image:: http://chris.emmery.nl/dump/shed.png
:alt: Pipeline

Important Note
''''''''''''''

This repository is currently in alpha development, so don't expect any stable
functionality until this part is removed.


Dependencies
''''''''''''

.. _Frog: https://languagemachines.github.io/frog/
.. _LaMachine: https://proycon.github.io/LaMachine/
.. _spaCy: https://spacy.io/

Omesa currently heavily relies on ``numpy``, ``scipy`` and ``sklearn``. To use
Frog_ as a Dutch back-end, we strongly recommend using LaMachine_. For
English, there is a spaCy_ wrapper available.

Omesa Only - End-To-End In 2 Minutes
------------------------------------

With the end-to-end ``Experiment`` pipeline and a configuration dictionary,
several experiments or set-ups can be ran and evaluated with a very minimal
piece of code. One of the test examples provided is that of n-gram
classification of Wikipedia documents. In this experiment, we are provided with
a toy set n_gram.csv that features 10 articles about Machine Learning, and 10
random other articles. To run the experiment, the following configuration is used:

Example
'''''''

.. _`n-gram classification`: https://github.com/cmry/omesa/blob/master/examples/n_gram.py
.. _`n_gram.csv`: https://github.com/cmry/omesa/blob/master/examples/n_gram.csv

With the end-to-end ``Experiment`` pipeline and a configuration dictionary,
several experiments or set-ups can be ran and evaluated with a very minimal
piece of code. One of the test examples provided is that of `n-gram classification`_
of Wikipedia documents. In this experiment, we are provided with a toy set
`n_gram.csv`_ that features 10 articles about Machine Learning, and 10 random
other articles. To run the experiment, the following configuration is used:

.. code-block:: python

from omesa.experiment import Experiment
from omesa.featurizer import Ngrams

conf = {
"gram_experiment": {
"name": "gram_experiment",
"train_data": ["./n_gram.csv"],
"has_header": True,
"features": [Ngrams(level='char', n_list=[3])],
"text_column": 1,
"label_column": 0,
"folds": 10,
"save": ("log")
}
}

for experiment, configuration in conf.items():
Experiment(configuration)

This will ten-fold cross validate performance on the ``.csv``, selecting text
and label columns and indicating a header is present in the ``.csv`` document.
We provide the ``Ngrams`` function and parameters to be used as features, and
store the log.

Output
''''''

The log file will be printed during run time, as well as stored in the
script's directory. The output of the current experiment is as follows:

.. code-block:: json
---- Omesa ----

Config:

feature: char_ngram
n_list: [3]

name: gram_experiment
seed: 42

Sparse train shape: (20, 1301)

Performance on test set:

precision recall f1-score support

DF 0.83 0.50 0.62 10
ML 0.64 0.90 0.75 10

avg / total 0.74 0.70 0.69 20


Experiment took 0.2 seconds

----------

Adding own Features
-------------------

Here's an example of the most minimum word frequency feature class:

.. code-block:: python

class SomeFeaturizer(object):

def __init__(self, some_params):
"""Set parameters for SomeFeaturizer."""
self.name = 'hookname'
self.some_params = some_params

def transform(self, raw, parse):
"""Return a dictionary of feature values."""
return Counter([x for x in raw])

This returns a ``{word: frequency}`` dict per instance that can easily be
transformed into a sparse matrix.

Acknowledgements
----------------

.. _AMiCA: http://www.amicaproject.be/

Part of the work on Omesa was carried out in the context of the
AMiCA_ (IWT SBO-project 120007) project, funded by the government agency for
Innovation by Science and Technology (IWT).