26 Jul
2011
26 Jul
'11
6:06 a.m.
2011/7/26 Siddhartha Gadgil
I have been making programs for mathematical applications (low-dimensional topology) in Haskell, which I find a delight to code in. However, the execution is slow, and this seems to be because recursively defined functions seem to be recomputed. For example f(100) needs f(15) which needs f(7) ... The dependencies are not obvious to the compiler. I was looking for a way to retain the values of a specific function in memory. Is there some way to do this.
It seems you are looking for memoization. Have a look at the comparison between slow/memoized_fib at this page http://www.haskell.org/haskellwiki/Memoization#Memoization_with_recursion Cheers, Thu