add pseudo-random number generation example

examples/pseudo-random/prandom.py

@@ -0,0 +1,36 @@
+from pyaccell import Automata
+from pyaccell import create_rule
+from pyaccell import vec_to_list
+from sys import argv
+from math import log2
+
+def transition(state, neighbour):
+    if (state == 1) and neighbour[1] < 2:
+        return 0
+    if (state == 1) and neighbour[1] > 3:
+        return 0
+    if (state == 0) and neighbour[1] == 3:
+        return 1
+
+    return state
+
+
+def random(max):
+    states = 2
+    rule = create_rule(transition, states)
+    ca = Automata(rule, states)
+    if (max > ca.sim_width * ca.sim_height):
+        ca = Automata(rule, states, max / 1024, 1024)
+    ca.run(3)
+    output = vec_to_list(ca.output)
+    binary = ''.join(map(str, output))
+    num = int(binary, 2)
+    return (num % max)
+
+if __name__ == '__main__':
+    if len(argv) != 2:
+        print("Usage: main.py <maximum value>")
+        exit(1)
+    _max = int(argv[1])
+    n = random(_max)
+    print(n)