'Compute sources from data (operates inplace).'

def _transform(self, data):

    if (self.pca_mean_ is not None):
        data -= self.pca_mean_[:, None]
    pca_data = np.dot(self.pca_components_[:self.n_components_], data)
    sources = np.dot(self.unmixing_matrix_, pca_data)
    return sources
