Brandon S. Allbery KF8NH wrote:
On Apr 26, 2008, at 9:02 , Richard Kelsall wrote:
I'm now wondering why my splitAtRK function in the following code makes it run in 11 seconds given a parameter of 2500000 but it takes 14 seconds when I change it to splitAt. Am I accidentally invoking
It's somewhat unusual to build the standard libraries with -O2, I think. (It can be done but the build takes a very long time.)
Also, 11 vs. 14 seconds seems not that much of a difference when you're talking 2500000 items, especially given how inefficient Haskell lists (Strings are lists) are.
Yes, well spotted. If I lower the compile level from -O2 to -O the splitAtRK version takes 14.5 seconds vs 14 seconds for the built-in version. Thank you. That solves the puzzle. For the benchmarks I expect they use a default packaged GHC, I don't imagine I could get them to use specially compiled libraries to bump up the GHC score. Which gives an interesting dilemma of whether I could get away with adding a small relevant snippet of library code to the program in order to give it -O2 level compilation. I wonder how much the other compilers optimise their library code. Richard.