From 1ac63d456439978ed0badbf7e94fe085402466c6 Mon Sep 17 00:00:00 2001 From: Gertjan van den Burg Date: Fri, 31 Jul 2015 00:04:46 +0200 Subject: added randbelow and shuffle methods --- SyncRNG.py | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'SyncRNG.py') diff --git a/SyncRNG.py b/SyncRNG.py index 7137439..7ef6fd6 100644 --- a/SyncRNG.py +++ b/SyncRNG.py @@ -4,11 +4,16 @@ used to seed and pull numbers from the RNG. """ +from __future__ import division + +from warnings import warn as _warn + import syncrng class SyncRNG(object): def __init__(self, seed=0): + self.BPF = 32 self.seed = seed self.state = syncrng.seed(seed) @@ -19,3 +24,24 @@ class SyncRNG(object): def rand(self): return self.randi() * 2.3283064365387e-10 + + def randbelow(self, n): + maxsize = 1<= maxsize: + _warn("Underlying random generator does not supply \n" + "enough bits to choose from a population range this " + "large.\n") + return int(self.rand() * n) + rem = maxsize % n + limit = (maxsize - rem) / maxsize + r = self.rand() + while r >= limit: + r = self.rand() + return int(r*maxsize) % n + + def shuffle(self, x): + y = x[:] + for i in reversed(range(1, len(y))): + j = self.randbelow(i+1) + y[i], y[j] = y[j], y[i] + return y -- cgit v1.2.3