下载和日志值在java [英] underflow and log values in java

问题描述

我有一个关于在机器学习模型中处理小概率值的问题。

避免下溢问题的标准方法是从小的浮点数乘以结果是使用log（x）而不是x

假设x = 0.50，其日志是log（x）= - 0.301029996

以稍后恢复的值exp（log（ x））！= x这是

0.740055574！= 0.50

那么，如何使用对数有用的处理下溢？

解决方案

这与溢出无关。在第一个日志中，您可以计算基数10中的 log ，而不是自然对数。您可以这样做：

提高 10 ^ log（x）以获取 x ，或使用自然对数。

I have a question in regard to dealing with small probabilities values in machine learning models.

The standard way to avoid underflow problems which results from multiplying small floating-point numbers is to use log(x) instead of x

suppose that x=0.50 the log of which is log(x)=-0.301029996

to recover x later on the value of exp(log(x)) != x that is

0.740055574 != 0.50

So, how is using the logarithm is useful to deal with underflow??

解决方案

This has nothing to do with the overflow. In the first log, you compute the log in base 10, instead of the natural logarithm. You can do this:

raise 10^log(x) to get back x, or use the natural logarithm.

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