fix undefined variables

prody/dynamics/plotting.py

@@ -260,6 +260,8 @@ def showProjection(ensemble, modes, *args, **kwargs):
     use_weights = kwargs.pop('use_weights', False)
     weights = kwargs.pop('weights', ensemble.getData('size'))
 
+    num = projection.shape[0]
+
     use_labels = kwargs.pop('use_labels', True)
     labels = kwargs.pop('label', None)
     if labels is None:
@@ -271,11 +273,12 @@ def showProjection(ensemble, modes, *args, **kwargs):
                 labels = modes.getModel()._labels.tolist()
                 LOGGER.info('using labels from LDA model')
 
-    if labels is not None and len(labels) != projection.shape[0]:
+    if labels is not None and len(labels) != num:
         raise ValueError('label should have the same length as ensemble')
 
     c = kwargs.pop('c', 'b')
     colors = kwargs.pop('color', c)
+    colors_dict = {}
     if isinstance(colors, np.ndarray):
         colors = tuple(colors)
     if isinstance(colors, (str, tuple)) or colors is None:
@@ -291,6 +294,11 @@ def showProjection(ensemble, modes, *args, **kwargs):
     else:
         raise TypeError('color must be a string or a list or a dict if labels are provided')
 
+    if labels is not None and len(colors_dict) == 0:
+        cycle_colors = plt.rcParams['axes.prop_cycle'].by_key()['color']
+        for i, label in enumerate(set(labels)):
+            colors_dict[label] = cycle_colors[i % len(cycle_colors)]
+
     if projection.ndim == 1 or projection.shape[1] == 1:
         by_time = not kwargs.pop('show_density', True)
         by_time = kwargs.pop('by_time', by_time)
@@ -329,8 +337,6 @@ def showProjection(ensemble, modes, *args, **kwargs):
         raise ValueError('Projection onto up to 3 modes can be shown. '
                          'You have given {0} mode.'.format(len(modes)))
 
-    num = projection.shape[0]
-
     markers = kwargs.pop('marker', 'o')
     if isinstance(markers, str) or markers is None:
         markers = [markers] * num