fix: AFHMM+SAC: add safeguard for when the optimizer does not find any constraint and returns None.

Fixes: #40

Author: levaphenyl

nilmtk_contrib/disaggregate/afhmm_sac.py

@@ -209,7 +209,11 @@ def disaggregate_thread(self, test_mains,index,d):
                 u = time.time()
                 prob = cvx.Problem(expression, constraints)
                 prob.solve(solver=cvx.SCS,verbose=False, warm_start=True)
-                s_ = [i.value for i in cvx_state_vectors]
+                s_ = [
+                    np.zeros((len(test_mains), self.default_num_states)) if i.value is None
+                    else i.value
+                    for i in cvx_state_vectors
+                ]
 
         prediction_dict = {}
         for appliance_id in range(self.num_appliances):