Remove matplotlib as a requirement (#2542)

* Remove matplotlib as a requirement

* Install matplotlib in travis

* Update some pylint

* Fix test to work

* Fix funny import error

* Remove namespace changes

* Just wrap matplotlib in try... except

* Rebase, remove import test

* Add bash script to confirm matplotlib is optional

Author: ColCarroll

.travis.yml

@@ -30,6 +30,7 @@ env:
   - PYTHON_VERSION=3.6 FLOATX='float64' TESTCMD="--durations=10 --cov-append pymc3/tests/test_variational_inference.py pymc3/tests/test_updates.py"
 script:
   - . ./scripts/test.sh $TESTCMD
+  - . ./scripts/confirm_mpl_optional.sh
 
 after_success:
   - coveralls

pymc3/__init__.py

@@ -22,7 +22,6 @@
 from .backends.tracetab import *
 
 from .plots import *
-
 from .tests import test
 
 from .data import *

pymc3/plots/autocorrplot.py

@@ -1,7 +1,11 @@
 import itertools
-import matplotlib.pyplot as plt
 import numpy as np
 
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
+
 from .utils import get_default_varnames, get_axis
 
 

pymc3/plots/compareplot.py

@@ -1,5 +1,8 @@
-import matplotlib.pyplot as plt
 import numpy as np
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
 
 
 def compareplot(comp_df, insample_dev=True, se=True, dse=True, ax=None,

pymc3/plots/energyplot.py

@@ -1,7 +1,10 @@
 import warnings
 
-import matplotlib.pyplot as plt
 import numpy as np
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
 from .kdeplot import kdeplot
 
 
@@ -35,6 +38,9 @@ def energyplot(trace, kind='kde', figsize=None, ax=None, legend=True,
     ax : matplotlib axes
     """
 
+    if ax is None:
+        _, ax = plt.subplots(figsize=figsize)
+
     try:
         energy = trace['energy']
     except KeyError:

pymc3/plots/forestplot.py

@@ -1,5 +1,8 @@
-from matplotlib import gridspec
-import matplotlib.pyplot as plt
+try:
+    import matplotlib.pyplot as plt
+    from matplotlib import gridspec
+except ImportError:  # mpl is optional
+    pass
 import numpy as np
 from pymc3.diagnostics import gelman_rubin
 from pymc3.stats import quantiles, hpd
@@ -102,18 +105,18 @@ def _plot_tree(ax, y, ntiles, show_quartiles, plot_kwargs):
     if show_quartiles:
         # Plot median
         ax.plot(ntiles[2], y, color=plot_kwargs.get('color', 'blue'),
-                        marker=plot_kwargs.get('marker', 'o'),
-                        markersize=plot_kwargs.get('markersize', 4))
+                marker=plot_kwargs.get('marker', 'o'),
+                markersize=plot_kwargs.get('markersize', 4))
         # Plot quartile interval
         ax.errorbar(x=(ntiles[1], ntiles[3]), y=(y, y),
-                        linewidth=plot_kwargs.get('linewidth', 2),
-                        color=plot_kwargs.get('color', 'blue'))
+                    linewidth=plot_kwargs.get('linewidth', 2),
+                    color=plot_kwargs.get('color', 'blue'))
 
     else:
         # Plot median
         ax.plot(ntiles[1], y, marker=plot_kwargs.get('marker', 'o'),
-                            color=plot_kwargs.get('color', 'blue'),
-                            markersize=plot_kwargs.get('markersize', 4))
+                color=plot_kwargs.get('color', 'blue'),
+                markersize=plot_kwargs.get('markersize', 4))
 
     # Plot outer interval
     ax.errorbar(x=(ntiles[0], ntiles[-1]), y=(y, y),

pymc3/plots/kdeplot.py

@@ -1,7 +1,11 @@
-import matplotlib.pyplot as plt
 import numpy as np
 from scipy.signal import gaussian, convolve
 
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
+
 
 def kdeplot(values, label=None, shade=0, ax=None, kwargs_shade=None, **kwargs):
     """

pymc3/plots/posteriorplot.py

@@ -1,5 +1,9 @@
 from collections import OrderedDict
-import matplotlib.pyplot as plt
+
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
 import numpy as np
 
 from .artists import plot_posterior_op
@@ -88,7 +92,8 @@ def get_trace_dict(tr, varnames):
             fig, ax = plt.subplots(figsize=figsize)
         plot_posterior_op(transform(trace), ax=ax, kde_plot=kde_plot,
                           point_estimate=point_estimate, round_to=round_to,
-                          alpha_level=alpha_level, ref_val=ref_val, rope=rope, text_size=text_size, **kwargs)
+                          alpha_level=alpha_level, ref_val=ref_val, rope=rope,
+                          text_size=text_size, **kwargs)
     else:
         if varnames is None:
             varnames = get_default_varnames(trace.varnames, plot_transformed)

pymc3/plots/traceplot.py

@@ -1,4 +1,7 @@
-import matplotlib.pyplot as plt
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
 import numpy as np
 
 from .artists import histplot_op, kdeplot_op

pymc3/plots/utils.py

@@ -1,4 +1,7 @@
-import matplotlib.pyplot as plt
+try:
+    import matplotlib.pyplot as plt
+except ImportError:  # mpl is optional
+    pass
 import numpy as np
 # plotting utilities can all be in this namespace
 from ..util import get_default_varnames  # pylint: disable=unused-import