fix copy_sample for initial state objects, fixes #75

pyhsmm/internals/initial_state.py

 from __future__ import division
 import numpy as np
+import copy
 
 import pyhsmm
 from pyhsmm.util.general import top_eigenvector
@@ -41,6 +42,11 @@ class UniformInitialState(object):
     def clear_caches(self):
         pass
 
+    def copy_sample(self, new_model):
+        new = copy.copy(self)
+        new.model = new_model
+        return new
+
 class HMMInitialState(Categorical):
     def __init__(self,model,init_state_concentration=None,pi_0=None):
         self.model = model
@@ -73,7 +79,6 @@ class HMMInitialState(Categorical):
     def clear_caches(self):
         pass
 
-
     def meanfieldupdate(self,expected_initial_states_list):
         super(HMMInitialState,self).meanfieldupdate(None,expected_initial_states_list)
 
@@ -85,6 +90,10 @@ class HMMInitialState(Categorical):
         super(HMMInitialState,self).max_likelihood(
                 data=samples,weights=expected_states_list)
 
+    def copy_sample(self, new_model):
+        new = copy.deepcopy(self)
+        new.model = new_model
+        return new
 
 class StartInZero(GibbsSampling,MaxLikelihood):
     def __init__(self,num_states,**kwargs):
@@ -100,6 +109,11 @@ class StartInZero(GibbsSampling,MaxLikelihood):
     def max_likelihood(*args,**kwargs):
         pass
 
+    def copy_sample(self, new_model):
+        new = copy.copy(self)
+        new.model = new_model
+        return new
+
 class HSMMInitialState(HMMInitialState):
     @property
     def steady_state_distribution(self):
@@ -112,4 +126,3 @@ class HSMMInitialState(HMMInitialState):
 
     def clear_caches(self):
         self._steady_state_distribution = None
-

pyhsmm/models.py

@@ -472,7 +472,7 @@ class _HMMGibbsSampling(_HMMBase,ModelGibbsSampling):
         new = copy.copy(self)
         new.obs_distns = [o.copy_sample() for o in self.obs_distns]
         new.trans_distn = self.trans_distn.copy_sample()
-        new.init_state_distn = self.init_state_distn.copy_sample()
+        new.init_state_distn = self.init_state_distn.copy_sample(new)
         new.states_list = [s.copy_sample(new) for s in self.states_list]
         return new