Deprecated Constant class (#2452)

* Moved Constant to subclass of Continuous

* Added missing distributions from distributions api docs

* Changed Constant to be subclass of Distribution

* Reverted changes and added deprecation warning for Constant

* Moved Constant reference in init

* Moved Constant reference in init

* Added Constant to discrete.rst

* Fixed import error

* Removed duplicate/redundant warning for ConstantDist

Author: fonnesbeck

docs/source/api/distributions/continuous.rst

@@ -7,23 +7,28 @@ Continuous
 
    Uniform
    Flat
+   HalfFlat
    Normal
+   HalfNormal
+   SkewNormal
    Beta
    Exponential
    Laplace
    StudentT
+   StudentTpos
    Cauchy
    HalfCauchy
    Gamma
    Weibull
-   StudentTpos
    Lognormal
    ChiSquared
-   HalfNormal
    Wald
    Pareto
    InverseGamma
    ExGaussian
+   VonMises
+   Triangular
+   Gumbel
 
 .. automodule:: pymc3.distributions.continuous
    :members:

docs/source/api/distributions/discrete.rst

@@ -6,15 +6,18 @@ Discrete
 .. autosummary::
 
    Binomial
+   ZeroInflatedBinomial
    BetaBinomial
    Bernoulli
    Poisson
+   ZeroInflatedPoisson
    NegativeBinomial
-   ConstantDist
    ZeroInflatedPoisson
    DiscreteUniform
    Geometric
    Categorical
+   DiscreteWeibull
+   Constant
 
 .. automodule:: pymc3.distributions.discrete
    :members:

pymc3/distributions/discrete.py

@@ -3,6 +3,7 @@
 import theano
 import theano.tensor as tt
 from scipy import stats
+import warnings
 
 from pymc3.util import get_variable_name
 from .dist_math import bound, factln, binomln, betaln, logpow
@@ -555,6 +556,8 @@ class Constant(Discrete):
     """
 
     def __init__(self, c, *args, **kwargs):
+        warnings.warn("Constant has been deprecated. We recommend using a Determinstic object instead.",
+                    DeprecationWarning)
         super(Constant, self).__init__(*args, **kwargs)
         self.mean = self.median = self.mode = self.c = c = tt.as_tensor_variable(c)
 
@@ -578,11 +581,7 @@ def _repr_latex_(self, name=None, dist=None):
         return r'${} \sim \text{{Constant}}()$'.format(name)
 
 
-def ConstantDist(*args, **kwargs):
-    import warnings
-    warnings.warn("ConstantDist has been deprecated. In future, use Constant instead.",
-                  DeprecationWarning)
-    return Constant(*args, **kwargs)
+ConstantDist = Constant
 
 
 class ZeroInflatedPoisson(Discrete):