Merge pull request #2798 from pymc-devs/slice_competence

Removed preference for slice sampler for continuous variables

Author: fonnesbeck

pymc3/step_methods/slicer.py

@@ -97,7 +97,8 @@ def astep(self, q0, logp):
     @staticmethod
     def competence(var, has_grad):
         if var.dtype in continuous_types:
-            if not var.shape or var.shape.ndim == 1:
+            if not has_grad and (var.shape is None or var.shape.ndim == 1):
                 return Competence.PREFERRED
             return Competence.COMPATIBLE
         return Competence.INCOMPATIBLE
+