Resolved issues with transformations

pymc4/distributions/continuous.py

@@ -12,6 +12,7 @@
     UnitContinuousDistribution,
     BoundedContinuousDistribution,
 )
+from pymc4.distributions import transforms
 from .half_student_t import HalfStudentT as TFPHalfStudentT
 
 
@@ -1080,6 +1081,12 @@ class Pareto(BoundedContinuousDistribution):
         Scale parameter (scale > 0).
     """
 
+    def _init_transform(self, transform):
+        if transform is None:
+            return transforms.LowerBound(self.lower_limit())
+        else:
+            return transform
+
     def __init__(self, name, concentration, scale, **kwargs):
         super().__init__(name, concentration=concentration, scale=scale, **kwargs)
 

pymc4/distributions/discrete.py

@@ -5,6 +5,7 @@
     PositiveDiscreteDistribution,
     BoundedDiscreteDistribution,
 )
+from pymc4.distributions import transforms
 
 __all__ = [
     "Bernoulli",
@@ -67,10 +68,10 @@ def _init_distribution(conditions, **kwargs):
         return tfd.Bernoulli(probs=probs, **kwargs)
 
     def lower_limit(self):
-        return 0
+        return 0.0
 
     def upper_limit(self):
-        return 1
+        return 1.0
 
 
 class Binomial(BoundedDiscreteDistribution):
@@ -124,7 +125,7 @@ def _init_distribution(conditions, **kwargs):
         return tfd.Binomial(total_count=total_count, probs=probs, **kwargs)
 
     def lower_limit(self):
-        return 0
+        return 0.0
 
     def upper_limit(self):
         return self._distribution.total_count
@@ -200,7 +201,7 @@ def _init_distribution(conditions, **kwargs):
         )
 
     def lower_limit(self):
-        return 0
+        return 0.0
 
     def upper_limit(self):
         return self._distribution.total_count
@@ -306,7 +307,7 @@ def _init_distribution(conditions, **kwargs):
         return tfd.FiniteDiscrete(outcomes, probs=probs, **kwargs)
 
     def lower_limit(self):
-        return 0
+        return 0.0
 
     def upper_limit(self):
         return len(self._distribution.probs)
@@ -353,6 +354,12 @@ class Geometric(BoundedDiscreteDistribution):
     # Another example for a wrong type used on the tensorflow side
     _test_value = 2.0  # type: ignore
 
+    def _init_transform(self, transform):
+        if transform is None:
+            return transforms.LowerBound(self.lower_limit())
+        else:
+            return transform
+
     def __init__(self, name, probs, **kwargs):
         super().__init__(name, probs=probs, **kwargs)
 
@@ -362,7 +369,7 @@ def _init_distribution(conditions, **kwargs):
         return tfd.Geometric(probs=probs, **kwargs)
 
     def lower_limit(self):
-        return 1
+        return 1.0
 
     def upper_limit(self):
         return float("inf")
@@ -760,7 +767,7 @@ def _init_distribution(conditions, **kwargs):
         return tfd.OrderedLogistic(cutpoints=cutpoints, loc=loc, **kwargs)
 
     def lower_limit(self):
-        return 0
+        return 0.0
 
     def upper_limit(self):
         return len(self._distribution.cutpoints)

pymc4/distributions/distribution.py

@@ -277,6 +277,12 @@ class DiscreteDistribution(Distribution):
 
 
 class BoundedDistribution(Distribution):
+    def _init_transform(self, transform):
+        if transform is None:
+            return transforms.Interval(self.lower_limit(), self.upper_limit())
+        else:
+            return transform
+
     @abc.abstractmethod
     def lower_limit(self):
         raise NotImplementedError
@@ -331,6 +337,12 @@ def upper_limit(self):
 class PositiveDiscreteDistribution(BoundedDiscreteDistribution):
     _test_value = 1
 
+    def _init_transform(self, transform):
+        if transform is None:
+            return transforms.Log()
+        else:
+            return transform
+
     def lower_limit(self):
         return 0
 

pymc4/distributions/transforms.py

@@ -3,7 +3,7 @@
 
 from tensorflow_probability import bijectors as tfb
 
-__all__ = ["Log", "Sigmoid"]
+__all__ = ["Log", "Sigmoid", "LowerBound", "UpperBound", "Interval"]
 
 
 class JacobianPreference(enum.Enum):
@@ -113,13 +113,13 @@ def inverse_log_det_jacobian(self, z):
         return self._transform.forward_log_det_jacobian(z)
 
 
-class Log(Transform):
-    name = "log"
+class BackwardTransform(Transform):
+    """Base class for Transforms with Jacobian Preference as Backward"""
+
     JacobianPreference = JacobianPreference.Backward
 
-    def __init__(self):
-        # NOTE: We actually need the inverse to match PyMC3, do we?
-        self._transform = tfb.Exp()
+    def __init__(self, transform):
+        self._transform = transform
 
     def forward(self, x):
         return self._transform.inverse(x)
@@ -134,21 +134,48 @@ def inverse_log_det_jacobian(self, z):
         return self._transform.forward_log_det_jacobian(z, self._transform.forward_min_event_ndims)
 
 
-class Sigmoid(Transform):
+class Log(BackwardTransform):
+    name = "log"
+
+    def __init__(self):
+        # NOTE: We actually need the inverse to match PyMC3, do we?
+        transform = tfb.Exp()
+        super().__init__(transform)
+
+
+class Sigmoid(BackwardTransform):
     name = "sigmoid"
-    JacobianPreference = JacobianPreference.Backward
 
     def __init__(self):
-        self._transform = tfb.Sigmoid()
+        transform = tfb.Sigmoid()
+        super().__init__(transform)
 
-    def forward(self, x):
-        return self._transform.inverse(x)
 
-    def inverse(self, z):
-        return self._transform.forward(z)
+class LowerBound(BackwardTransform):
+    """"Transformation to interval [lower_limit, inf]"""
 
-    def forward_log_det_jacobian(self, x):
-        return self._transform.inverse_log_det_jacobian(x, self._transform.inverse_min_event_ndims)
+    name = "lowerbound"
 
-    def inverse_log_det_jacobian(self, z):
-        return self._transform.forward_log_det_jacobian(z, self._transform.forward_min_event_ndims)
+    def __init__(self, lower_limit):
+        transform = tfb.Chain([tfb.Shift(lower_limit), tfb.Exp()])
+        super().__init__(transform)
+
+
+class UpperBound(BackwardTransform):
+    """"Transformation to interval [-inf, upper_limit]"""
+
+    name = "upperbound"
+
+    def __init__(self, upper_limit):
+        transform = tfb.Chain([tfb.Shift(upper_limit), tfb.Scale(-1), tfb.Exp()])
+        super().__init__(transform)
+
+
+class Interval(BackwardTransform):
+    """"Transformation to interval [lower_limit, upper_limit]"""
+
+    name = "interval"
+
+    def __init__(self, lower_limit, upper_limit):
+        transform = tfb.Sigmoid(low=lower_limit, high=upper_limit)
+        super().__init__(transform)

pymc4/flow/transformed_executor.py

@@ -80,7 +80,7 @@ def make_transformed_model(dist, transform, state):
 
     # Important:
     # I have no idea yet, how to make that beautiful.
-    # Here we indicate the distribution is already autotransformed nto to get in the infinite loop
+    # Here we indicate the distribution is already autotransformed not to get in the infinite loop
     dist.model_info["autotransformed"] = True
 
     # 2. here decide on logdet computation, this might be effective