From 12a20f8cd76db62328bb2051e84c61b5efbc676e Mon Sep 17 00:00:00 2001 From: "Eric S. Raymond" Date: Wed, 24 Apr 2019 01:26:38 -0400 Subject: [PATCH] Portable LCG in place - grr, Python's random changed incompaibly in 3.2. --- sst.py | 52 +++++++++++++++++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 19 deletions(-) diff --git a/sst.py b/sst.py index b8e7985..1fdcbd6 100755 --- a/sst.py +++ b/sst.py @@ -36,44 +36,57 @@ docpath = (".", "doc/", "/usr/share/doc/sst/") def _(st): return gettext.gettext(st) -# This is all encapsulated not just for logging but because someday -# we'll probably want to replace it with something like an LCG that -# can be forward-ported off Python. Thee only function we need is one to -# return a variate uniformly-distributed over [0, 1). - -import random +# Rolling our own LCG because Python changed its incompatibly in 3.2. +# Thus, we need to have our own to be 2/3 polyglot, which will also +# be helpful when we forwrard-port. class randomizer: + # LCG PRNG parameters tested against + # Knuth vol. 2. by the authors of ADVENT + LCG_A = 1093 + LCG_C = 221587 + LCG_M = 1048576 + + @staticmethod + def random(): + old_x = game.lcg_x + game.lcg_x = (randomizer.LCG_A * game.lcg_x + randomizer.LCG_C) % randomizer.LCG_M + return old_x / randomizer.LCG_M; + @staticmethod def withprob(p): - v = random.random() - if logfp: - logfp.write("#withprob(%.2f) -> %s\n" % (p, v < p)) + v = randomizer.random() + #if logfp: + # logfp.write("#withprob(%.2f) -> %s\n" % (p, v < p)) return v < p @staticmethod def integer(*args): - s = random.randrange(*args) - if logfp: - logfp.write("#randrange%s -> %s\n" % (args, s)) - return s + v = randomizer.random() + if len(args) == 1: + v = int(v * args[0]) + else: + v = args[0] + int(v * (args[1] - args[0])) + #if logfp: + # logfp.write("#integer%s -> %s\n" % (args, v)) + return int(v) @staticmethod def real(*args): - v = random.random() + v = randomizer.random() if len(args) == 1: v *= args[0] # from [0, args[0]) elif len(args) == 2: v = args[0] + v*(args[1]-args[0]) # from [args[0], args[1]) - if logfp: - logfp.write("#real%s -> %f\n" % (args, v)) + #if logfp: + # logfp.write("#real%s -> %f\n" % (args, v)) return v @staticmethod def seed(n): - if logfp: - logfp.write("#seed(%d)\n" % n) - random.seed(n) + #if logfp: + # logfp.write("#seed(%d)\n" % n) + game.lcg_x = n % randomizer.LCG_M GALSIZE = 8 # Galaxy size in quadrants NINHAB = (GALSIZE * GALSIZE // 2) # Number of inhabited worlds @@ -470,6 +483,7 @@ class Gamestate: self.iscloaked = False # Cloaking device on? self.ncviol = 0 # Algreon treaty violations self.isviolreported = False # We have been warned + self.lcg_x = 0 # LCG generator value def remkl(self): return sum([q.klingons for (_i, _j, q) in list(self.state.traverse())]) def recompute(self): -- 2.31.1