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really performance-critical code. Also this will tell you whether your performance problems are due to strictness/boxing or something else. It should be possible to obtain the same performance as C++ (or better).

Are you shure about this? And why are you shure?

One can never be 100% sure, but your application is numerical and experience suggests that numerical code can often be optimised to yield code similar or better in performance than C. The pseudoknot benchmark (a while ago now) was a good example.

You put the blame on me for the bad performance of my code,

I didn't mean to give that impression, sorry. Optimising Haskell code is a delicate art which requires experience and sometimes a deep knowledge of GHC's optimiser. This is a real problem, and we readily accept that. Cheers, Simon