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pytorch/torch/distributions/geometric.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

114 lines
4.3 KiB
Python

from numbers import Number
import torch
from torch.distributions import constraints
from torch.distributions.distribution import Distribution
from torch.distributions.utils import broadcast_all, probs_to_logits, logits_to_probs, lazy_property
from torch.nn.functional import binary_cross_entropy_with_logits
__all__ = ['Geometric']
class Geometric(Distribution):
r"""
Creates a Geometric distribution parameterized by :attr:`probs`,
where :attr:`probs` is the probability of success of Bernoulli trials.
It represents the probability that in :math:`k + 1` Bernoulli trials, the
first :math:`k` trials failed, before seeing a success.
Samples are non-negative integers [0, :math:`\inf`).
Example::
>>> # xdoctest: +IGNORE_WANT("non-deterinistic")
>>> m = Geometric(torch.tensor([0.3]))
>>> m.sample() # underlying Bernoulli has 30% chance 1; 70% chance 0
tensor([ 2.])
Args:
probs (Number, Tensor): the probability of sampling `1`. Must be in range (0, 1]
logits (Number, Tensor): the log-odds of sampling `1`.
"""
arg_constraints = {'probs': constraints.unit_interval,
'logits': constraints.real}
support = constraints.nonnegative_integer
def __init__(self, probs=None, logits=None, validate_args=None):
if (probs is None) == (logits is None):
raise ValueError("Either `probs` or `logits` must be specified, but not both.")
if probs is not None:
self.probs, = broadcast_all(probs)
else:
self.logits, = broadcast_all(logits)
probs_or_logits = probs if probs is not None else logits
if isinstance(probs_or_logits, Number):
batch_shape = torch.Size()
else:
batch_shape = probs_or_logits.size()
super(Geometric, self).__init__(batch_shape, validate_args=validate_args)
if self._validate_args and probs is not None:
# Add an extra check beyond unit_interval
value = self.probs
valid = value > 0
if not valid.all():
invalid_value = value.data[~valid]
raise ValueError(
"Expected parameter probs "
f"({type(value).__name__} of shape {tuple(value.shape)}) "
f"of distribution {repr(self)} "
f"to be positive but found invalid values:\n{invalid_value}"
)
def expand(self, batch_shape, _instance=None):
new = self._get_checked_instance(Geometric, _instance)
batch_shape = torch.Size(batch_shape)
if 'probs' in self.__dict__:
new.probs = self.probs.expand(batch_shape)
if 'logits' in self.__dict__:
new.logits = self.logits.expand(batch_shape)
super(Geometric, new).__init__(batch_shape, validate_args=False)
new._validate_args = self._validate_args
return new
@property
def mean(self):
return 1. / self.probs - 1.
@property
def mode(self):
return torch.zeros_like(self.probs)
@property
def variance(self):
return (1. / self.probs - 1.) / self.probs
@lazy_property
def logits(self):
return probs_to_logits(self.probs, is_binary=True)
@lazy_property
def probs(self):
return logits_to_probs(self.logits, is_binary=True)
def sample(self, sample_shape=torch.Size()):
shape = self._extended_shape(sample_shape)
tiny = torch.finfo(self.probs.dtype).tiny
with torch.no_grad():
if torch._C._get_tracing_state():
# [JIT WORKAROUND] lack of support for .uniform_()
u = torch.rand(shape, dtype=self.probs.dtype, device=self.probs.device)
u = u.clamp(min=tiny)
else:
u = self.probs.new(shape).uniform_(tiny, 1)
return (u.log() / (-self.probs).log1p()).floor()
def log_prob(self, value):
if self._validate_args:
self._validate_sample(value)
value, probs = broadcast_all(value, self.probs)
probs = probs.clone(memory_format=torch.contiguous_format)
probs[(probs == 1) & (value == 0)] = 0
return value * (-probs).log1p() + self.probs.log()
def entropy(self):
return binary_cross_entropy_with_logits(self.logits, self.probs, reduction='none') / self.probs