32bit NaN check

[simon place]

i was looking to check for a vary rare situation when i get NaN, its deep in some computation that i don't want to rearrange to preclude it.

so i want to check for it, but i seem to need to add the Math package, and convert to 64bit, this is a very high price to pay for something that comes up less than 1 in 10e7+ cases, is there some other way? ( i was surprised there isn't a 32bit isNaN(). )

[Matthew Kane]

The NaN check is simply return f != f.

On Jun 16, 2013 7:22 PM, "simon place" <simon...@googlemail.com> wrote:

i was looking to check for a vary rare situation when i get NaN, its deep in some computation that i don't want to rearrange to preclude it.

so i want to check for it, but i seem to need to add the Math package, and convert to 64bit, this is a very high price to pay for something that comes up less than 1 in 10e7+ cases, is there some other way? ( i was surprised there isn't a 32bit isNaN(). )

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[simon place]

thanks, never would have guessed that.

i'll see what that does for speed, a bit poor on readability though so i guess i'll just add a comment.

[Dan Kortschak]

... or add and call:

func isNaN(f float32) bool { return f != f }

[simon place]

yes, and it will probably be in-lined for no speed penalty?

[Dave Cheney]

Yup, should do.
http://dave.cheney.net/2012/02/11/how-the-go-language-improves-expressiveness-without-sacrificing-runtime-performance

On Mon, Jun 17, 2013 at 10:28 AM, simon place
<simon...@googlemail.com> wrote:
> yes, and it will probably be in-lined for no speed penalty?
>