Add exercise 1.23

chapter-1/ex-23.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+
+import numpy as np
+import random
+
+registered_events = {}
+
+# We'll define events as predicates:
+# Also I'll use some decorators, just to show off
+
+# the decorator:
+def event(event_pred):
+    key = event_pred.__name__
+    val = (event_pred, 0)
+    registered_events[key] = val
+    return event_pred
+
+@event
+def omega(value):
+    return True
+
+@event
+def a1(value):
+    return value % 2 == 0
+
+@event
+def b1(value):
+    return value <= 4
+
+@event
+def ab1(value):
+    return a1(value) and b1(value)
+
+@event
+def a2(value):
+    return value % 2 == 0
+
+@event
+def b2(value):
+    return value <= 5
+
+@event
+def ab2(value):
+    return a2(value) and b2(value)
+
+random.seed()
+def dice_experiment(reps):
+    for i in range(reps):
+        r = random.randint(1,6)
+        for key, value in registered_events.items():
+            func, count = value
+            if func(r):
+                count += 1
+            newval = (func, count)
+            registered_events[key] = newval
+
+dice_experiment(1000)
+
+total = registered_events["omega"][1]
+print(f"Total = ", registered_events["omega"][1]/total)
+print(f"P^(A1) = ", registered_events["a1"][1]/total)
+print(f"P^(B1) = ", registered_events["b1"][1]/total)
+print(f"P^(A1)P^(B1) = ", registered_events["a1"][1]/total * registered_events["b1"][1]/total)
+print(f"P^(AB1) = ", registered_events["ab1"][1]/total)
+print(f"P^(A2) = ", registered_events["a2"][1]/total)
+print(f"P^(B2) = ", registered_events["b2"][1]/total)
+print(f"P^(A2)P^(B2) = ", registered_events["a2"][1]/total * registered_events["b2"][1]/total)
+print(f"P^(AB2) = ", registered_events["ab2"][1]/total)
+
+"""Example output:
+
+Total =  1.0
+P^(A1) =  0.494
+P^(B1) =  0.667
+P^(A1)P^(B1) =  0.329498
+P^(AB1) =  0.329
+P^(A2) =  0.494
+P^(B2) =  0.835
+P^(A2)P^(B2) =  0.41249
+P^(AB2) =  0.329"""