在Python中乘法和供电时防止溢出错误

时间:2012-02-22 14:49:45

标签: python numeric multiplication limits

在调用下面定义的函数biased_random时,如何防止错误?参数scalebias的限制是为了防止大数或小数问题?

def biased_random(scale, bias):
  return random.random() ** bias * scale

>>> sum(biased_random(1000, 10) for x in range(100)) / 100
64.94178302276364

>>> sum(biased_random(1000, 100000) for x in range(100)) / 100
0.0

>>> sum(biased_random(1000, 0.002) for x in range(100)) / 100
998.0704866851909

1 个答案:

答案 0 :(得分:1)

我会使用sys.maxint来确定溢出点是什么。然后除以它或将其与你的数字进行比较:

r = random.random()
if sys.maxint ** (1.0/bias) < r:
    print "overflow imminent"
elif sys.maxint/float(scale) < r ** bias:
    print "overflow imminent"
else:
    print "overflow unlikely. To infinity, and beyond..."

希望这有帮助