8000 BUG: Large distances between `start` and `stop` in `np.linspace()` result in non-finite values · Issue #21585 · numpy/numpy · GitHub
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BUG: Large distances between start and stop in np.linspace() result in non-finite values #21585

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honno opened this issue May 24, 2022 · 3 comments
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BUG: Large distances between start and stop in np.linspace() result in non-finite values #21585

honno opened this issue May 24, 2022 · 3 comments
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00 - Bug 57 - Close? Issues which may be closable unless discussion continued

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@honno
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honno commented May 24, 2022 •
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Describe the issue:

I'm guessing some internal logic causes this issue, like in #20226. Given it's such an edge case this is probably not worth fixing, just thought I'd write an issue for prosperity's sake.

Reproduce the code example:

>>> np.linspace(-9.9792015476736e+291, 1.7976931348623157e+308, 1)
RuntimeWarning: overflow encountered in double_scalars
  delta = stop - start
RuntimeWarning: invalid value encountered in multiply
  y = y * delta
array([nan])  # expected -9.9792015476736e+291
>>> np.linspace(-9.9792015476736e+291, 1.7976931348623157e+308, 5)
... same warnings ...
array([ nan, inf, inf, inf, 1.79769313e+308] )  # expected finite values in-between

NumPy/Python version information:

1.23.0.dev0+1084.g5ab08cfa8 3.8.12 (default, Mar 13 2022, 19:12:08)
[GCC 9.4.0]
@honno honno added the 00 - Bug label May 24, 2022
@honno honno mentioned this issue May 24, 2022
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@bashtage
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This is a well-known limitation due to the limits of floating-point numbers. This can only be described as "by design". The only possible solution would be to warn when linspace produces non-finite values.

@LeonaTaric LeonaTaric mentioned this issue Aug 13, 2022
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@seberg
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seberg commented Aug 22, 2022

I agree with @bashtage. Unless someone argues from a non hypothesis angle why this is particularly important, I think this is simply one of the many floating-point surprises that can happen and that we should simply not do anything about it.

@seberg seberg added the 57 - Close? Issues which may be closable unless discussion continued label Aug 22, 2022
@rossbar
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rossbar commented Aug 22, 2022

I also agree, closing. Please feel free to reopen if there are further specific instances of users getting bit by this.

@rossbar rossbar closed this as not planned Won't fix, can't repro, duplicate, stale Aug 22, 2022
@honno honno mentioned this issue Sep 30, 2022
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