Change the interfaces in trasformation base class
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@ -272,6 +272,10 @@ def check_type(data_type, value_type, name):
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def raise_none_error(name):
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raise ValueError(f"{name} should be specified. Value cannot be None")
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@constexpr
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def raise_not_impl_error(name):
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raise ValueError(f"{name} function should be implemented for non-linear transformation")
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@constexpr
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def check_distribution_name(name, expected_name):
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if name != expected_name:
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@ -18,7 +18,7 @@ from mindspore._checkparam import Validator as validator
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from mindspore.common import dtype as mstype
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import mindspore.nn as nn
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from .distribution import Distribution
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from ._utils.utils import check_type
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from ._utils.utils import check_type, raise_not_impl_error
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class TransformedDistribution(Distribution):
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"""
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@ -56,6 +56,7 @@ class TransformedDistribution(Distribution):
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self._distribution = distribution
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self._is_linear_transformation = bijector.is_constant_jacobian
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self.exp = P.Exp()
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self.log = P.Log()
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@property
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def bijector(self):
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@ -69,37 +70,49 @@ class TransformedDistribution(Distribution):
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def is_linear_transformation(self):
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return self._is_linear_transformation
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def _cdf(self, value):
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def _cdf(self, *args, **kwargs):
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r"""
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.. math::
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Y = g(X)
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P(Y <= a) = P(X <= g^{-1}(a))
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"""
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inverse_value = self.bijector.inverse(value)
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return self.distribution.cdf(inverse_value)
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inverse_value = self.bijector("inverse", *args, **kwargs)
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return self.distribution("cdf", inverse_value)
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def _log_prob(self, value):
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def _log_cdf(self, *args, **kwargs):
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return self.log(self._cdf(*args, **kwargs))
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def _survival_function(self, *args, **kwargs):
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return 1.0 - self._cdf(*args, **kwargs)
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def _log_survival(self, *args, **kwargs):
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return self.log(self._survival_function(*args, **kwargs))
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def _log_prob(self, *args, **kwargs):
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r"""
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.. math::
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Y = g(X)
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Py(a) = Px(g^{-1}(a)) * (g^{-1})'(a)
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\log(Py(a)) = \log(Px(g^{-1}(a))) + \log((g^{-1})'(a))
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"""
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inverse_value = self.bijector.inverse(value)
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unadjust_prob = self.distribution.log_prob(inverse_value)
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log_jacobian = self.bijector.inverse_log_jacobian(value)
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inverse_value = self.bijector("inverse", *args, **kwargs)
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unadjust_prob = self.distribution("log_prob", inverse_value)
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log_jacobian = self.bijector("inverse_log_jacobian", *args, **kwargs)
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return unadjust_prob + log_jacobian
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def _prob(self, value):
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return self.exp(self._log_prob(value))
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def _prob(self, *args, **kwargs):
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return self.exp(self._log_prob(*args, **kwargs))
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def _sample(self, shape):
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org_sample = self.distribution.sample(shape)
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return self.bijector.forward(org_sample)
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def _sample(self, *args, **kwargs):
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org_sample = self.distribution("sample", shape)
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return self.bijector("forward", org_sample)
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def _mean(self):
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def _mean(self, *args, **kwargs):
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"""
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Note:
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This function maybe overridden by derived class.
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"""
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return self.bijector.forward(self.distribution.mean())
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if not self.is_linear_transformation:
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raise_not_impl_error(mean)
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return self.bijector("forward", self.distribution("mean"))
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