Added cell_stats example

examples/python-api/script.py

@@ -0,0 +1,22 @@
+#!/usr/bin/python3
+
+from pyosys import libyosys as ys
+
+import matplotlib.pyplot as plt
+import numpy as np
+
+design = ys.Design()
+ys.run_pass("read_verilog ../../tests/simple/fiedler-cooley.v", design);
+ys.run_pass("prep", design)
+ys.run_pass("opt -full", design)
+
+cell_stats = {}
+for module in design.selected_whole_modules_warn():
+  for cell in module.selected_cells():
+    if cell.type.str() in cell_stats:
+      cell_stats[cell.type.str()] += 1
+    else:
+      cell_stats[cell.type.str()] = 1
+plt.bar(range(len(cell_stats)), height = list(cell_stats.values()),align='center')
+plt.xticks(range(len(cell_stats)), list(cell_stats.keys()))
+plt.show()