def testBijector(self):
with self.test_session():
bijector = identity_lib.Identity()
self.assertEqual("identity", bijector.name)
x = [[[0.], [1.]]]
self.assertAllEqual(x, bijector.forward(x).eval())
self.assertAllEqual(x, bijector.inverse(x).eval())
self.assertAllEqual(0.,
bijector.inverse_log_det_jacobian(x).eval())
self.assertAllEqual(0.,
bijector.forward_log_det_jacobian(x).eval())
def testScalarCongruency(self):
with self.test_session():
bijector = identity_lib.Identity()
bijector_test_util.assert_scalar_congruency(bijector,
lower_x=-2.,
upper_x=2.)
def __init__(self,
distribution,
bijector=None,
batch_shape=None,
event_shape=None,
validate_args=False,
name=None):
"""Construct a Transformed Distribution.
Args:
distribution: The base distribution instance to transform. Typically an
instance of `Distribution`.
bijector: The object responsible for calculating the transformation.
Typically an instance of `Bijector`. `None` means `Identity()`.
batch_shape: `integer` vector `Tensor` which overrides `distribution`
`batch_shape`; valid only if `distribution.is_scalar_batch()`.
event_shape: `integer` vector `Tensor` which overrides `distribution`
`event_shape`; valid only if `distribution.is_scalar_event()`.
validate_args: Python `bool`, default `False`. When `True` distribution
parameters are checked for validity despite possibly degrading runtime
performance. When `False` invalid inputs may silently render incorrect
outputs.
name: Python `str` name prefixed to Ops created by this class. Default:
`bijector.name + distribution.name`.
"""
parameters = locals()
name = name or (("" if bijector is None else bijector.name) +
distribution.name)
with ops.name_scope(name, values=[event_shape, batch_shape]):
# For convenience we define some handy constants.
self._zero = constant_op.constant(0, dtype=dtypes.int32, name="zero")
self._empty = constant_op.constant([], dtype=dtypes.int32, name="empty")
if bijector is None:
bijector = identity_lib.Identity(validate_args=validate_args)
# We will keep track of a static and dynamic version of
# self._is_{batch,event}_override. This way we can do more prior to graph
# execution, including possibly raising Python exceptions.
self._override_batch_shape = self._maybe_validate_shape_override(
batch_shape, distribution.is_scalar_batch(), validate_args,
"batch_shape")
self._is_batch_override = _logical_not(_logical_equal(
_ndims_from_shape(self._override_batch_shape), self._zero))
self._is_maybe_batch_override = bool(
tensor_util.constant_value(self._override_batch_shape) is None or
tensor_util.constant_value(self._override_batch_shape).size != 0)
self._override_event_shape = self._maybe_validate_shape_override(
event_shape, distribution.is_scalar_event(), validate_args,
"event_shape")
self._is_event_override = _logical_not(_logical_equal(
_ndims_from_shape(self._override_event_shape), self._zero))
self._is_maybe_event_override = bool(
tensor_util.constant_value(self._override_event_shape) is None or
tensor_util.constant_value(self._override_event_shape).size != 0)
# To convert a scalar distribution into a multivariate distribution we
# will draw dims from the sample dims, which are otherwise iid. This is
# easy to do except in the case that the base distribution has batch dims
# and we're overriding event shape. When that case happens the event dims
# will incorrectly be to the left of the batch dims. In this case we'll
# cyclically permute left the new dims.
self._needs_rotation = _logical_and(
self._is_event_override,
_logical_not(self._is_batch_override),
_logical_not(distribution.is_scalar_batch()))
override_event_ndims = _ndims_from_shape(self._override_event_shape)
self._rotate_ndims = _pick_scalar_condition(
self._needs_rotation, override_event_ndims, 0)
# We'll be reducing the head dims (if at all), i.e., this will be []
# if we don't need to reduce.
self._reduce_event_indices = math_ops.range(
self._rotate_ndims - override_event_ndims, self._rotate_ndims)
self._distribution = distribution
self._bijector = bijector
super(TransformedDistribution, self).__init__(
dtype=self._distribution.dtype,
reparameterization_type=self._distribution.reparameterization_type,
validate_args=validate_args,
allow_nan_stats=self._distribution.allow_nan_stats,
parameters=parameters,
# We let TransformedDistribution access _graph_parents since this class
# is more like a baseclass than derived.
graph_parents=(distribution._graph_parents + # pylint: disable=protected-access
bijector.graph_parents),
name=name)