Source code for bob.learn.em.train

#!/usr/bin/env python
# vim: set fileencoding=utf-8 :
# Tiago de Freitas Pereira <tiago.pereira@idiap.ch>
# Fri Feb 13 13:18:10 2015 +0200
#
# Copyright (C) 2011-2015 Idiap Research Institute, Martigny, Switzerland
import numpy
import bob.learn.em
import logging

logger = logging.getLogger('bob.learn.em')


[docs]def train(trainer, machine, data, max_iterations=50, convergence_threshold=None, initialize=True, rng=None, check_inputs=True): """ Trains a machine given a trainer and the proper data **Parameters**: trainer : one of :py:class:`KMeansTrainer`, :py:class:`MAP_GMMTrainer`, :py:class:`ML_GMMTrainer`, :py:class:`ISVTrainer`, :py:class:`IVectorTrainer`, :py:class:`PLDATrainer`, :py:class:`EMPCATrainer` A trainer mechanism machine : one of :py:class:`KMeansMachine`, :py:class:`GMMMachine`, :py:class:`ISVBase`, :py:class:`IVectorMachine`, :py:class:`PLDAMachine`, :py:class:`bob.learn.linear.Machine` A container machine data : array_like <float, 2D> The data to be trained max_iterations : int The maximum number of iterations to train a machine convergence_threshold : float The convergence threshold to train a machine. If None, the training procedure will stop with the iterations criteria initialize : bool If True, runs the initialization procedure rng : :py:class:`bob.core.random.mt19937` The Mersenne Twister mt19937 random generator used for the initialization of subspaces/arrays before the EM loop check_inputs: Shallow checks in the inputs. Check for inf and NaN """ if check_inputs and type(data) is numpy.ndarray: if numpy.isinf(numpy.sum(data)): raise ValueError("Please, check your inputs; numpy.inf detected in `data` ") if numpy.isnan(numpy.sum(data)): raise ValueError("Please, check your inputs; numpy.nan detected in `data` ") # Initialization if initialize: if rng is not None: trainer.initialize(machine, data, rng) else: trainer.initialize(machine, data) trainer.e_step(machine, data) average_output = 0 average_output_previous = 0 if hasattr(trainer, "compute_likelihood"): average_output = trainer.compute_likelihood(machine) for i in range(max_iterations): logger.debug("Iteration = %d/%d", i+1, max_iterations) average_output_previous = average_output trainer.m_step(machine, data) trainer.e_step(machine, data) if hasattr(trainer, "compute_likelihood"): average_output = trainer.compute_likelihood(machine) if type(machine) is bob.learn.em.KMeansMachine: logger.debug("average euclidean distance = %f", average_output) else: logger.debug("log likelihood = %f", average_output) convergence_value = abs((average_output_previous - average_output) / average_output_previous) logger.debug("convergence value = %f", convergence_value) # Terminates if converged (and likelihood computation is set) if convergence_threshold != None and convergence_value <= convergence_threshold: logger.info("EM training converged after %d iterations with convergence value %f", i, convergence_value) break if hasattr(trainer, "finalize"): trainer.finalize(machine, data)
[docs]def train_jfa(trainer, jfa_base, data, max_iterations=10, initialize=True, rng=None): """ Trains a :py:class:`bob.learn.em.JFABase` given a :py:class:`bob.learn.em.JFATrainer` and the proper data **Parameters**: trainer : :py:class:`bob.learn.em.JFATrainer` A JFA trainer mechanism jfa_base : :py:class:`bob.learn.em.JFABase` A container machine data : [[:py:class:`bob.learn.em.GMMStats`]] The data to be trained max_iterations : int The maximum number of iterations to train a machine initialize : bool If True, runs the initialization procedure rng : :py:class:`bob.core.random.mt19937` The Mersenne Twister mt19937 random generator used for the initialization of subspaces/arrays before the EM loops """ if initialize: if rng is not None: trainer.initialize(jfa_base, data, rng) else: trainer.initialize(jfa_base, data) # V Subspace logger.info("V subspace estimation...") for i in range(max_iterations): logger.debug("Iteration = %d/%d", i+1, max_iterations) trainer.e_step_v(jfa_base, data) trainer.m_step_v(jfa_base, data) trainer.finalize_v(jfa_base, data) # U subspace logger.info("U subspace estimation...") for i in range(max_iterations): logger.debug("Iteration = %d/%d", i+1, max_iterations) trainer.e_step_u(jfa_base, data) trainer.m_step_u(jfa_base, data) trainer.finalize_u(jfa_base, data) # D subspace logger.info("D subspace estimation...") for i in range(max_iterations): logger.debug("Iteration = %d/%d", i+1, max_iterations) trainer.e_step_d(jfa_base, data) trainer.m_step_d(jfa_base, data) trainer.finalize_d(jfa_base, data)