fix import and counting to make it work (#74)

Author: stevenhua0320

src/diffpy/srmise/modelcluster.py

@@ -1408,8 +1408,8 @@ def prune(self):
 if __name__ == "__main__":
     from numpy.random import randn
 
-    from diffpy.srmise.modelevaluators import AICc
-    from diffpy.srmise.peaks import GaussianOverR
+    from diffpy.srmise.modelevaluators.aicc import AICc
+    from diffpy.srmise.peaks.gaussianoverr import GaussianOverR
 
     pf = GaussianOverR(0.7)
     res = 0.01

src/diffpy/srmise/modelparts.py

@@ -558,7 +558,7 @@ def npars(self, count_fixed=True):
         if count_fixed:
             return self._owner.npars
         else:
-            return (self.free is True).sum()
+            return np.sum(self.free)
 
     def __str__(self):
         """Return string representation of ModelPart parameters."""