add updated exercise

exercises/exerciseC/plot.py

@@ -0,0 +1,67 @@
+import sys
+import collections
+import numpy as np
+
+dts = collections.defaultdict(dict)
+
+for fname in sys.argv[1:]:
+    values = open(fname).read().split()
+    n1 = int(values[0])
+    n2 = int(values[1])
+    dt = float(values[2])
+
+    dts[n1][n2] = dt
+
+print(dts)
+N1 = max(dts)
+N2 = max(max(v) for v in dts.values())
+
+print(N1, N2)
+
+x = np.empty((N1 + 1, N2 + 1))
+for n1, values in dts.items():
+    for n2, v in values.items():
+        x[n1, n2] = v
+
+x[:, 0] = np.nan
+x[0, :] = np.nan
+
+print(x)
+
+from matplotlib import pyplot
+
+fig, axes = pyplot.subplots()
+im = axes.imshow(x, origin='lower')
+axes.set_ylabel('# processes')
+axes.set_xlabel('# threads')
+axes.spines[['right', 'top']].set_visible(False)
+axes.set_title('time')
+fig.colorbar(im, ax=axes, label='s')
+
+fig_small, axes = pyplot.subplots()
+im = axes.imshow(x[:5, :5], origin='lower')
+axes.set_ylabel('# processes')
+axes.set_xlabel('# threads')
+axes.spines[['right', 'top']].set_visible(False)
+axes.set_title('time')
+fig_small.colorbar(im, ax=axes, label='s')
+
+workers = np.arange(N1 + 1)[:, None] * np.arange(N2 + 1)
+speedup = x[1,1] / x
+
+speedup[:, 0] = np.nan
+speedup[0, :] = np.nan
+
+figs, axes = pyplot.subplots()
+im = axes.imshow(speedup, origin='lower')
+axes.set_ylabel('# processes')
+axes.set_xlabel('# threads')
+axes.spines[['right', 'top']].set_visible(False)
+axes.set_title('speedup')
+figs.colorbar(im, ax=axes, label='s')
+
+fig.savefig('time.svg')
+fig_small.savefig('time_inset.svg')
+figs.savefig('speedup.svg')
+
+pyplot.show()