adding changes so you can provide step without step_kwargs every time

bilby/core/sampler/pymc3.py

@@ -62,12 +62,12 @@ class Pymc3(MCMCSampler):
         live_plot_kwargs=None, compute_convergence_checks=True, use_mmap=False)
 
     def __init__(self, likelihood, priors, outdir='outdir', label='label',
-                 use_ratio=False, plot=False, draws=1000,
+                 use_ratio=False, plot=False,
                  skip_import_verification=False, **kwargs):
         Sampler.__init__(self, likelihood, priors, outdir=outdir, label=label,
                          use_ratio=use_ratio, plot=plot,
                          skip_import_verification=skip_import_verification, **kwargs)
-        self.draws = draws
+        self.draws  = self.__kwargs['draws']
         self.chains = self.__kwargs['chains']
 
     @staticmethod
@@ -401,7 +401,7 @@ class Pymc3(MCMCSampler):
                             sms = self.step_method[key]
                         else:
                             sms = [self.step_method[key]]
-
+                            print(sms)
                         for sm in sms:
                             if sm.lower() not in step_methods:
                                 raise ValueError("Using invalid step method '{}'".format(self.step_method[key]))
@@ -454,10 +454,16 @@ class Pymc3(MCMCSampler):
                         if curmethod == 'nuts':
                             if nuts_kwargs is not None:
                                 args = nuts_kwargs
-                            else:
+                            elif step_kwargs is not None:
                                 args = step_kwargs.get('nuts', {})
+                            else : 
+                                args = {}
                         else:
-                            args = step_kwargs.get(curmethod, {})
+                            if step_kwargs is not None :   
+                                args = step_kwargs.get(curmethod, {})
+                                print(args)
+                            else : 
+                                args = {}
                         self.kwargs['step'].append(pymc3.__dict__[step_methods[curmethod]](vars=[self.pymc3_priors[key]], **args))
         else:
             with self.pymc3_model: