surface 17: correction in optimized solution

exercises/surface17_depolarizing_optimized.py

@@ -148,10 +148,10 @@ def main(relative_samples=10000, resolution=16):
     ax.set_title('Pseudothreshold of Surface-17, depolarizing noise')
     ax.set_xscale('log')
     ax.set_yscale('log')
-    ax.plot(pRange, x_failure_rates, '-x', label='logical X error')
-    ax.plot(pRange, y_failure_rates, '-x', label='logical Y error')
-    ax.plot(pRange, z_failure_rates, '-x', label='logical Z error')
-    ax.plot(pRange, total_failure_rates, '-x', label='any logical error')
+    ax.plot(pRange, logical_error_rates[:,0], '-x', label='logical X error')
+    ax.plot(pRange, logical_error_rates[:,1], '-x', label='logical Y error')
+    ax.plot(pRange, logical_error_rates[:,2], '-x', label='logical Z error')
+    ax.plot(pRange, logical_error_rates.sum(axis=1), '-x', label='any logical error')
     ax.plot(pRange, pRange, 'k:', alpha=0.5)
     ax.legend()
     fig.tight_layout()