Bugfix

urbs.py

@@ -1643,22 +1643,17 @@ def plot(prob, com, sit, timesteps=None, power_unit='MW', energy_unit='MWh'):
 
     # sorting plot elements
 	# calculate standard deviation possibly normed by mean value, takes ~10-100ms
-	std = pd.DataFrame(np.zeros_like(created.tail(1)),
-                       index=created.index[-1:]+1, columns=created.columns)
-    for col in std.columns:
-        std[col] = np.std(created[col])
-        # norming by mean value
-        std[col] = std[col] / np.mean(created[col])
-        # keep order and only place base load at bottom
-        #if std[i] < 0.01:
-        #   std[i] = -1
-        #else:
-        #   std[i] = i
-        #i = i+1  	
-	# sort created ascencing with std i.e. base load first
-    created = created.append(std)
-    new_columns = created.columns[created.ix[created.last_valid_index()].argsort()]
-    created = created[new_columns][:-1]
+    if len(created.columns) > 1:
+        std = pd.DataFrame(np.zeros_like(created.tail(1)),
+                           index=created.index[-1:]+1, columns=created.columns)
+        for col in std.columns:
+            std[col] = np.std(created[col])
+            # norming by mean value
+            std[col] = std[col] / np.mean(created[col])
+        # sort created ascencing with std i.e. base load first
+        created = created.append(std)
+        new_columns = created.columns[created.ix[created.last_valid_index()].argsort()]
+        created = created[new_columns][:-1]
 
     # PLOT CREATED
     ax0 = plt.subplot(gs[0])