pytorch/torch/distributions/log_normal.py
joncrall 4618371da5 Integrate xdoctest - Rebased (#82797)
This is a new version of #15648 based on the latest master branch.

Unlike the previous PR where I fixed a lot of the doctests in addition to integrating xdoctest, I'm going to reduce the scope here. I'm simply going to integrate xdoctest, and then I'm going to mark all of the failing tests as "SKIP". This will let xdoctest run on the dashboards, provide some value, and still let the dashboards pass. I'll leave fixing the doctests themselves to another PR.

In my initial commit, I do the bare minimum to get something running with failing dashboards. The few tests that I marked as skip are causing segfaults. Running xdoctest results in 293 failed, 201 passed tests. The next commits will be to disable those tests. (unfortunately I don't have a tool that will insert the `#xdoctest: +SKIP` directive over every failing test, so I'm going to do this mostly manually.)

Fixes https://github.com/pytorch/pytorch/issues/71105

@ezyang
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82797
Approved by: https://github.com/ezyang
2022-08-12 02:08:01 +00:00

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1.9 KiB
Python

from torch.distributions import constraints
from torch.distributions.transforms import ExpTransform
from torch.distributions.normal import Normal
from torch.distributions.transformed_distribution import TransformedDistribution
__all__ = ['LogNormal']
class LogNormal(TransformedDistribution):
r"""
Creates a log-normal distribution parameterized by
:attr:`loc` and :attr:`scale` where::
X ~ Normal(loc, scale)
Y = exp(X) ~ LogNormal(loc, scale)
Example::
>>> # xdoctest: +IGNORE_WANT("non-deterinistic")
>>> m = LogNormal(torch.tensor([0.0]), torch.tensor([1.0]))
>>> m.sample() # log-normal distributed with mean=0 and stddev=1
tensor([ 0.1046])
Args:
loc (float or Tensor): mean of log of distribution
scale (float or Tensor): standard deviation of log of the distribution
"""
arg_constraints = {'loc': constraints.real, 'scale': constraints.positive}
support = constraints.positive
has_rsample = True
def __init__(self, loc, scale, validate_args=None):
base_dist = Normal(loc, scale, validate_args=validate_args)
super(LogNormal, self).__init__(base_dist, ExpTransform(), validate_args=validate_args)
def expand(self, batch_shape, _instance=None):
new = self._get_checked_instance(LogNormal, _instance)
return super(LogNormal, self).expand(batch_shape, _instance=new)
@property
def loc(self):
return self.base_dist.loc
@property
def scale(self):
return self.base_dist.scale
@property
def mean(self):
return (self.loc + self.scale.pow(2) / 2).exp()
@property
def mode(self):
return (self.loc - self.scale.square()).exp()
@property
def variance(self):
return (self.scale.pow(2).exp() - 1) * (2 * self.loc + self.scale.pow(2)).exp()
def entropy(self):
return self.base_dist.entropy() + self.loc