exB: add plot script with results from a student laptop

exercises/exerciseB/plot.py

@@ -0,0 +1,27 @@
+import pandas as pd
+from matplotlib import pyplot
+ 
+records = [
+    # (n_procs, time, description)
+    (1, 47.38, 'lc'),
+    (1, 44.36, 'mp'),
+    (2, 40.34, 'mp'),
+    (3, 46.79, 'mp'),
+    (4, 51.68, 'mp'),
+    (4, 51.63, 'mp'),
+]
+ 
+data = pd.DataFrame(records,
+                    columns=('n_procs', 'time', 'description'))
+ 
+fig, axes = pyplot.subplots()
+axes.set_xlabel('# threads/processes')
+axes.set_ylabel('time')
+sub = data[data.description=='lc']
+axes.plot(sub.n_procs, sub.time, 'ro')
+sub = data[data.description=='mp']
+axes.plot(sub.n_procs, sub.time, 'b--+')
+ 
+axes.set_ylim(0, data.time.max() * 1.2)
+ 
+pyplot.show()