andrewcoppin:
Donald Bruce Stewart wrote:
Some things to remember using Doubles:
* {-# OPTIONS -fexcess-precision #-} * -fvia-C * -fbang-patterns * -optc-O2 -optc-mfpmath=sse -optc-msse2 * -optc-march=pentium4
1. What do all those things do?
Check the GHC user's guide.
2. Is the effect actually that large?
1) {-# OPTIONS -fexcess-precision #- I've had this halved runtimes for runtimes for numeric-intensive programs. 2) -fvia-C Probably still worth 10% for Double-based stuff (maybe more). 3) -fbang-patterns Better than `seq` 4) -optc-O2 -optc-mfpmath=sse -optc-msse2 -optc-march=pentium4 Can be worth 0 to hmm, quite a few, percent, depending on the code. This is all assuming you've written low level code anyway, so that the effects of, say, using SSE instructions are actually apparent. -- Don