Make ArviZ a proper requirement

Author: ColCarroll

RELEASE-NOTES.md

@@ -9,6 +9,7 @@
 - Added `Matern12` covariance function for Gaussian processes. This is the Matern kernel with nu=1/2.
 - Progressbar reports number of divergences in real time, when available [#3547](https://github.com/pymc-devs/pymc3/pull/3547).
 - Sampling from variational approximation now allows for alternative trace backends [#3550].
+- [ArviZ](https://arviz-devs.github.io/arviz/) is now a requirement, and handles plotting, diagnostics, and statistical checks.
 
 ### Maintenance
 - Moved math operations out of `Rice`, `TruncatedNormal`, `Triangular` and `ZeroInflatedNegativeBinomial` `random` methods. Math operations on values returned by `draw_values` might not broadcast well, and all the `size` aware broadcasting is left to `generate_samples`. Fixes [#3481](https://github.com/pymc-devs/pymc3/issues/3481) and [#3508](https://github.com/pymc-devs/pymc3/issues/3508)

pymc3/plots/__init__.py

@@ -7,27 +7,8 @@
 import functools
 import sys
 import warnings
-try:
-    import arviz as az
-except ImportError:  # arviz is optional, throw exception when used
 
-    class _ImportWarner:
-        __all__ = []
-
-        def __init__(self, attr):
-            self.attr = attr
-
-        def __call__(self, *args, **kwargs):
-            raise ImportError(
-                "ArviZ is not installed. In order to use `{0.attr}`:\npip install arviz".format(self)
-            )
-
-    class _ArviZ:
-        def __getattr__(self, attr):
-            return _ImportWarner(attr)
-
-
-    az = _ArviZ()
+import arviz as az
 
 def map_args(func):
     swaps = [

pymc3/stats/__init__.py

@@ -1,36 +1,13 @@
-"""Statistical utility functions for PyMC
+"""Statistical utility functions for PyMC3
 
 Diagnostics and auxiliary statistical functions are delegated to the ArviZ library, a general
 purpose library for "exploratory analysis of Bayesian models." See
 https://arviz-devs.github.io/arviz/ for details.
 """
 import functools
-import sys
 import warnings
 
-try:
-    import arviz as az
-except ImportError:  # arviz is optional, throw exception when used
-
-    class _ImportWarner:
-        __all__ = []
-
-        def __init__(self, attr):
-            self.attr = attr
-
-        def __call__(self, *args, **kwargs):
-            raise ImportError(
-                "ArviZ is not installed. In order to use `{0.attr}`:\npip install arviz".format(
-                    self
-                )
-            )
-
-    class _ArviZ:
-        def __getattr__(self, attr):
-            return _ImportWarner(attr)
-
-    az = _ArviZ()
-
+import arviz as az
 
 def map_args(func):
     swaps = [("varnames", "var_names")]
@@ -41,28 +18,14 @@ def wrapped(*args, **kwargs):
             if old in kwargs and new not in kwargs:
                 warnings.warn(
                     "Keyword argument `{old}` renamed to `{new}`, and will be removed in "
-                    "pymc3 3.8".format(old=old, new=new)
+                    "pymc3 3.9".format(old=old, new=new)
                 )
                 kwargs[new] = kwargs.pop(old)
             return func(*args, **kwargs)
 
     return wrapped
 
 
-__all__ = [
-    "bfmi",
-    "compare",
-    "ess",
-    "geweke",
-    "hpd",
-    "loo",
-    "mcse",
-    "r2_score",
-    "rhat",
-    "summary",
-    "waic",
-]
-
 bfmi = map_args(az.bfmi)
 compare = map_args(az.compare)
 ess = map_args(az.ess)
@@ -77,31 +40,30 @@ def wrapped(*args, **kwargs):
 
 
 def gelman_rubin(*args, **kwargs):
-    warnings.warn("gelman_rubin has been deprecated. In future, use rhat instead.")
+    warnings.warn("gelman_rubin has been deprecated. In the future, use rhat instead.")
     return rhat(*args, **kwargs)
 
+gelman_rubin.__doc__ = rhat.__doc__
+
 
 def effective_n(*args, **kwargs):
-    warnings.warn("effective_n has been deprecated. In future, use ess instead.")
+    warnings.warn("effective_n has been deprecated. In the future, use ess instead.")
     return ess(*args, **kwargs)
 
+effective_n.__doc__ = ess.__doc__
 
-# Access to arviz stats: base stats provided by arviz
-for stat in az.stats.__all__:
-    setattr(sys.modules[__name__], stat, map_args(getattr(az.stats, stat)))
-
-__all__ = tuple(az.stats.__all__) + (
+__all__ = [
+    "bfmi",
     "compare",
+    "ess",
+    "geweke",
     "hpd",
     "loo",
+    "mcse",
     "r2_score",
+    "rhat",
     "summary",
     "waic",
-    "bfmi",
-    "ess",
-    "geweke",
-    "mcse",
-    "rhat",
-    "gelman_rubin",
-    "effective_n",
-)
+    "gelman_rubin",  # deprecated, remove after 3.8
+    "effective_n",  # deprecated, remove after 3.8
+]

requirements.txt

@@ -1,3 +1,4 @@
+arviz>=0.4.1
 theano>=1.0.4
 numpy>=1.13.0
 scipy>=0.18.1

setup.py

@@ -2,7 +2,6 @@
 from codecs import open
 from os.path import realpath, dirname, join
 from setuptools import setup, find_packages
-import sys
 import re
 
 DISTNAME = 'pymc3'
@@ -17,6 +16,7 @@
                'Programming Language :: Python :: 3',
                'Programming Language :: Python :: 3.5',
                'Programming Language :: Python :: 3.6',
+               'Programming Language :: Python :: 3.7',
                'License :: OSI Approved :: Apache Software License',
                'Intended Audience :: Science/Research',
                'Topic :: Scientific/Engineering',
@@ -61,8 +61,5 @@ def get_version():
           classifiers=classifiers,
           python_requires=">=3.5.4",
           install_requires=install_reqs,
-          extras_require={
-              "plots": ["arviz"],
-          },
           tests_require=test_reqs,
           test_suite='nose.collector')