Fix Combined Histogram Issue - Mark01 (#168)

* fresh start maro1

* adjust no of colours

* add comment

workflows/mark01.smk

@@ -25,6 +25,8 @@ metrics = ["AD","DL"]  # <-- configure distances here
 num_samples = 200 # <-- configure number of samples here
 
 # Errors <--- set the error rates here
+# TODO (Gordon): having other than 3 error rates may cause error in combined histograms rule
+# colour list has fixed length of 3
 selected_error_cond = ['IDEAL', 'TYPICAL', 'LARGE']
 all_error_cond = {
         member.name: member.value.dict()
@@ -148,7 +150,7 @@ rule make_combined_histograms:
         fig, axs = plt.subplots(1,1,tight_layout=True)
         fig.set_size_inches(7, 4)
         # Define colors for each histogram
-        colors = ['g', 'b', 'r', 'purple']
+        colors = ['g', 'b', 'r']
         # make combined histogram for all error conditions
         plot_data = []
         plot_label = []