Problem on windows with `_expm1`

haskell / math-functions

Special mathematical functions

BSD 2-Clause "Simplified" License

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Closed ggreif closed 7 years ago

ggreif commented 7 years ago

I'll just leave this here: cchalmers/plots#22

Strangely math-functions-0.2.0.2 compiles nicely, but cannot be loaded!?

Shimuuar commented 7 years ago

it's because compilation fails during linking. Can you compile simple console program which uses math-functions? Something like:

main = print $ expm1 1

ggreif commented 7 years ago

I cannot reproduce now, because I have math-functions-0.1.7.0 installed, and cannot upgrade. But looking at

expm1
exp the former is only available in VS2013 (and up) but the latter is present universally.

Could one make a CPP trick to detect it? Or a cabal install flag to fall back to exp(x) - 1 or such?

Shimuuar commented 7 years ago

Fallback to exp x - 1 goes contrary to purpose of expm1 so I guess only way forward is to implement expm1 in haskell

Surely windows is divine punishments for something

ggreif commented 7 years ago

@Shimuuar yep, I think reimplementing expm1 in Haskell when the library does not provide it is the way to go.

Shimuuar commented 7 years ago

Fixed in 0.2.1.0 (I hope). It would be nice if you would test it on windows.

log1p and expm1 are simply reexported from GHC.Float. They're methods of Floating type class.
On windows expm1 is implemented in pure haskell for older GHCs.

ggreif commented 7 years ago

@Shimuuar confirmed on windows, thanks!