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A comment on Cosine Implementation in C. Parent comment

Re:Cosine Implementation in C by kolbe on Friday March 31, 2023 @10:15AM (#35387478)
Why do you return x-x for inf or nan? I can't test now, but I imagine they both return nan?

I run a high performance math library in C#, and I'm always looking to improve.

https://github.com/matthewkolbe/LitMath

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Re:Cosine Implementation in C by jcranmer on Friday March 31, 2023 @10:55AM (#35388049)
Using the expression ensures that the FP exceptions are properly set. It also does quieting of sNaN or NaN payload propagation as appropriate.
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Re:Cosine Implementation in C by hurrrrrrrr on Friday March 31, 2023 @10:55AM (#35388051)
It's an easy way to return nan and set FE_INVALID. If you're not worried about floating point exceptions you can just return NaN directly. Idk how much C# even guarantees about the floating point operations and if it's applicable there.

https://en.cppreference.com/w/cpp/numeric/fenv/FE_exceptions

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