问题描述
以下错误是什么?
Warning: overflow encountered in exp
在scipy/numpy中使用Python通常是什么意思?我正在以对数形式计算比率，即log(a)+ log(b)，然后使用exp和logumexp的总和来取结果的指数，如下所示:
in scipy/numpy using Python generally mean? I'm computing a ratio in log form, i.e. log(a) + log(b) and then taking the exponent of the result, using exp, and using a sum with logsumexp, as follows:
c = log(a) + log(b)
c = c - logsumexp(c)
数组b中的某些值被有意地设置为0.它们的日志为-Inf.
some values in the array b are intentionally set to 0. Their log will be -Inf.
此警告可能是什么原因?谢谢.
What could be the cause of this warning? thanks.
推荐答案
在您的情况下，这意味着b在数组中的某个地方非常小，并且您得到一个数字( a/b或exp(log(a) - log(b)))对于您用于存储输出的数组的任何dtype(float32，float64等)都太大.
In your case, it means that b is very small somewhere in your array, and you're getting a number (a/b or exp(log(a) - log(b))) that is too large for whatever dtype (float32, float64, etc) the array you're using to store the output is.
Numpy可以配置为
Numpy can be configured to
- 忽略这些错误，
- 打印错误，但不发出警告以停止执行(默认)
- 记录错误，
- 提出警告
- 引发错误
- 调用用户定义的函数
请参见 numpy.seterr 以控制它的方式处理浮点数组中的下溢/上溢等.
See numpy.seterr to control how it handles having under/overflows, etc in floating point arrays.
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