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Rumale

Rumale (Ruby machine learning) is a machine learning library in Ruby. Rumale provides machine learning algorithms with interfaces similar to Scikit-Learn in Python. Rumale supports Support Vector Machine, Logistic Regression, Ridge, Lasso, Multi-layer Perceptron, Naive Bayes, Decision Tree, Gradient Tree Boosting, Random Forest, K-Means, Gaussian Mixture Model, DBSCAN, Spectral Clustering, Mutidimensional Scaling, t-SNE, Fisher Discriminant Analysis, Neighbourhood Component Analysis, Principal Component Analysis, Non-negative Matrix Factorization, and many other algorithms.

Installation

Add this line to your application's Gemfile:

gem 'rumale'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rumale

Documentation

Rumale API Documentation

Usage

Example 1. Pendigits dataset classification

Rumale provides function loading libsvm format dataset file. We start by downloading the pendigits dataset from LIBSVM Data web site.

$ wget https://www.csie.ntu.edu.tw/~cjlin/libsvmtools/datasets/multiclass/pendigits
$ wget https://www.csie.ntu.edu.tw/~cjlin/libsvmtools/datasets/multiclass/pendigits.t

Training of the classifier with Linear SVM and RBF kernel feature map is the following code.

require 'rumale'

# Load the training dataset.
samples, labels = Rumale::Dataset.load_libsvm_file('pendigits')

# Map training data to RBF kernel feature space.
transformer = Rumale::KernelApproximation::RBF.new(gamma: 0.0001, n_components: 1024, random_seed: 1)
transformed = transformer.fit_transform(samples)

# Train linear SVM classifier.
classifier = Rumale::LinearModel::SVC.new(reg_param: 0.0001)
classifier.fit(transformed, labels)

# Save the model.
File.open('transformer.dat', 'wb') { |f| f.write(Marshal.dump(transformer)) }
File.open('classifier.dat', 'wb') { |f| f.write(Marshal.dump(classifier)) }

Classifying testing data with the trained classifier is the following code.

require 'rumale'

# Load the testing dataset.
samples, labels = Rumale::Dataset.load_libsvm_file('pendigits.t')

# Load the model.
transformer = Marshal.load(File.binread('transformer.dat'))
classifier = Marshal.load(File.binread('classifier.dat'))

# Map testing data to RBF kernel feature space.
transformed = transformer.transform(samples)

# Classify the testing data and evaluate prediction results.
puts("Accuracy: %.1f%%" % (100.0 * classifier.score(transformed, labels)))

# Other evaluating approach
# results = classifier.predict(transformed)
# evaluator = Rumale::EvaluationMeasure::Accuracy.new
# puts("Accuracy: %.1f%%" % (100.0 * evaluator.score(results, labels)))

Execution of the above scripts result in the following.

$ ruby train.rb
$ ruby test.rb
Accuracy: 98.5%

Example 2. Cross-validation

require 'rumale'

# Load dataset.
samples, labels = Rumale::Dataset.load_libsvm_file('pendigits')

# Define the estimator to be evaluated.
lr = Rumale::LinearModel::LogisticRegression.new

# Define the evaluation measure, splitting strategy, and cross validation.
ev = Rumale::EvaluationMeasure::Accuracy.new
kf = Rumale::ModelSelection::StratifiedKFold.new(n_splits: 5, shuffle: true, random_seed: 1)
cv = Rumale::ModelSelection::CrossValidation.new(estimator: lr, splitter: kf, evaluator: ev)

# Perform 5-cross validation.
report = cv.perform(samples, labels)

# Output result.
mean_accuracy = report[:test_score].sum / kf.n_splits
puts "5-CV mean accuracy: %.1f%%" % (100.0 * mean_accuracy)

Execution of the above scripts result in the following.

$ ruby cross_validation.rb
5-CV mean accuracy: 95.5%

Speedup

Numo::Linalg

Rumale uses Numo::NArray for typed arrays. Loading the Numo::Linalg allows to perform matrix and vector product of Numo::NArray using BLAS libraries. Some machine learning algorithms frequently compute matrix and vector products, the execution speed of such algorithms can be expected to be accelerated.

Install Numo::Linalg gem.

$ gem install numo-linalg

In ruby script, just load Numo::Linalg along with Rumale.

require 'numo/linalg/autoloader'
require 'rumale'

Numo::Linalg allows user selection of background libraries for BLAS/LAPACK. Instead of fixing the background library, Numo::OpenBLAS and Numo::BLIS are available to simplify installation.

Numo::TinyLinalg

Numo::TinyLinalg is a subset library from Numo::Linalg consisting only of methods used in machine learning algorithms. Numo::TinyLinalg only supports OpenBLAS as a backend library for BLAS and LAPACK. If the OpenBLAS library is not found during installation, Numo::TinyLinalg downloads and builds that.

$ gem install numo-tiny_linalg

Load Numo::TinyLinalg instead of Numo::Linalg.

require 'numo/tiny_linalg'

Numo::Linalg = Numo::TinyLinalg

require 'rumale'

Parallel

Several estimators in Rumale support parallel processing. Parallel processing in Rumale is realized by Parallel gem, so install and load it.

$ gem install parallel

require 'parallel'
require 'rumale'

Estimators that support parallel processing have n_jobs parameter. When -1 is given to n_jobs parameter, all processors are used.

estimator = Rumale::Ensemble::RandomForestClassifier.new(n_jobs: -1, random_seed: 1)

Related Projects

Rumale::SVM provides support vector machine algorithms in LIBSVM and LIBLINEAR with Rumale interface.
Rumale::Torch provides the learning and inference by the neural network defined in torch.rb with Rumale interface.

License

The gem is available as open source under the terms of the BSD-3-Clause License.