Consider two versions of sin wrapped:
foreign import ccall "math.h sin"
c_sin_m :: CDouble -> IO CDouble
and
foreign import ccall "math.h sin"
c_sin :: CDouble -> CDouble
One can invoke them so:
mapM c_sin_m [1..n]
mapM (return . c_sin) [1..n]
On my computer with n = 10^7 the first
version never finishes, whereas the second
one calculates the result within seconds.
To give you my context, I need to call
a random variable generator multiple times,
so that it must return IO a.
Any explanation for this behavior?
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