def observed_perplexity(self, counts):
"""Compute perplexity = exp(entropy) of observed variables.
Perplexity is an information theoretic measure of the number of
clusters or latent classes. Perplexity is a real number in the range
[1, M], where M is model_num_clusters.
Args:
counts: A [V]-shaped array of multinomial counts.
Returns:
A [V]-shaped numpy array of perplexity.
"""
V, E, M, R = self._VEMR
if counts is not None:
counts = np.ones(V, dtype=np.int8)
assert counts.shape == (V, )
assert counts.dtype == np.int8
assert np.all(counts > 0)
observed_entropy = np.empty(V, dtype=np.float32)
for v in range(V):
beg, end = self._ragged_index[v:v + 2]
probs = np.dot(self._feat_cond[beg:end, :], self._vert_probs[v, :])
observed_entropy[v] = multinomial_entropy(probs, counts[v])
return np.exp(observed_entropy)
评论列表
文章目录