最小正float64数 [英] Smallest positive float64 number

问题描述

我需要找到一个尽可能接近零的numpy.float64值.

I need to find a numpy.float64 value that is as close to zero as possible.

Numpy提供了几个常数，它们可以执行类似的操作:

Numpy offers several constants that allow to do something similar:

• np.finfo(np.float64).eps = 2.2204460492503131e-16
• np.finfo(np.float64).tiny = 2.2250738585072014e-308

• np.finfo(np.float64).eps = 2.2204460492503131e-16
• np.finfo(np.float64).tiny = 2.2250738585072014e-308

它们都相当小，但是当我这样做时

These are both reasonably small, but when I do this

>>> x = np.finfo(np.float64).tiny
>>> x / 2
6.9533558078350043e-310

结果甚至更小.当使用即兴二进制搜索时，在将值四舍五入为0.0之前，我可以降低到大约1e-323.

the result is even smaller. When using an impromptu binary search I can get down to about 1e-323, before the value is rounded down to 0.0.

我在numpy中是否缺少此常量?或者，是否有 right 方法来做到这一点?

Is there a constant for this in numpy that I am missing? Alternatively, is there a right way to do this?

推荐答案

使用np.nextafter.

>>> import numpy as np
>>> np.nextafter(0, 1)
4.9406564584124654e-324
>>> np.nextafter(np.float32(0), np.float32(1))
1.4012985e-45

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