1# Copyright 2020 Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15import scipy.stats as osp_stats
16from jax.scipy.special import expit, logit
17
18from jax import lax
19from jax._src.numpy.util import _wraps
20
21
22@_wraps(osp_stats.logistic.logpdf, update_doc=False)
23def logpdf(x):
24  return lax.neg(x) - 2. * lax.log1p(lax.exp(lax.neg(x)))
25
26@_wraps(osp_stats.logistic.pdf, update_doc=False)
27def pdf(x):
28  return lax.exp(logpdf(x))
29
30@_wraps(osp_stats.logistic.ppf, update_doc=False)
31def ppf(x):
32  return logit(x)
33
34@_wraps(osp_stats.logistic.sf, update_doc=False)
35def sf(x):
36  return expit(lax.neg(x))
37
38@_wraps(osp_stats.logistic.isf, update_doc=False)
39def isf(x):
40  return -logit(x)
41
42@_wraps(osp_stats.logistic.cdf, update_doc=False)
43def cdf(x):
44  return expit(x)
45