vowpal-wabbit 8.6.1.dfsg1-1build3 (amd64 binary) in ubuntu hirsute

 Vowpal Wabbit is a fast online machine learning algorithm. The core
 algorithm is specialist gradient descent (GD) on a loss function
 (several are available). VW features:
  - flexible input data specification
  - speedy learning
  - scalability (bounded memory footprint, suitable for distributed
    computation)
  - feature pairing