test_gmm.py 文件源码

def test_train(self, params='wmc'):
        g = mixture.GMM(n_components=self.n_components,
                        covariance_type=self.covariance_type)
        g.weights_ = self.weights
        g.means_ = self.means
        g.covars_ = 20 * self.covars[self.covariance_type]

        # Create a training set by sampling from the predefined distribution.
        X = g.sample(n_samples=100)
        g = self.model(n_components=self.n_components,
                       covariance_type=self.covariance_type,
                       random_state=rng, min_covar=1e-1,
                       n_iter=1, init_params=params)
        g.fit(X)

        # Do one training iteration at a time so we can keep track of
        # the log likelihood to make sure that it increases after each
        # iteration.
        trainll = []
        for _ in range(5):
            g.params = params
            g.init_params = ''
            g.fit(X)
            trainll.append(self.score(g, X))
        g.n_iter = 10
        g.init_params = ''
        g.params = params
        g.fit(X)  # finish fitting

        # Note that the log likelihood will sometimes decrease by a
        # very small amount after it has more or less converged due to
        # the addition of min_covar to the covariance (to prevent
        # underflow).  This is why the threshold is set to -0.5
        # instead of 0.
        delta_min = np.diff(trainll).min()
        self.assertTrue(
            delta_min > self.threshold,
            "The min nll increase is %f which is lower than the admissible"
            " threshold of %f, for model %s. The likelihoods are %s."
            % (delta_min, self.threshold, self.covariance_type, trainll))