OT : Approximate / fast math libraries ?
Chris Jones
jonesc at hep.phy.cam.ac.uk
Sat Sep 1 10:28:28 UTC 2007
> Another poster mentioned that pentiums
> have hardware instructions for trig functions.
> If you are using them, there isn't much hope for speed up.
Out of interest, whats needs to be done to use these, some gcc flag ? My
profiling suggests that atan2(x,y) is taking ~ 50% of some method speed. Yes,
the methods is already fast, but still is this reasonable if hardware
instructions are being used. Is there some way I can check to see exactly
what is used ?
> These formulas will probably not be useful unless
> you know in advance the ranges of their arguments.
Yes, I considered coding up my own methods along this line, but figured
getting it correct was not a small amount of effort, and was hoping to find
some project that had done it for me.
cheers Chris
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