12 Feb
2007
12 Feb
'07
5:28 p.m.
On Mon, Feb 12, 2007 at 02:25:21PM -0800, Bryan O'Sullivan wrote:
David Roundy wrote:
I'm rather curious (if you're sill interested) how this'll be affected by the removal of the division from the inner loop. e.g.
go :: Double -> Double -> Int -> IO () go !x !y !i | i == 1000000000 = printf "%.6f\n" (x+y) | otherwise = go (x*y*(1.0/3)) (x*9) (i+1)
for (; i<1000000000; i++) { x = x*y*(1.0/3.0); y = x*9.0; }
GCC will do the transformation itself if you use -ffast-math. It requires the flag as the results aren't exactly numerically equivalent.
Ah, okay. Never mind, then. -- David Roundy Department of Physics Oregon State University