Hi, I discovered that in base /logBase/, the functions representing arbitrary logarithms, are defined in terms of two applications of /log/. /log/, the functions representing the natural logarithm, just pass responsibility on to some primitives. That is fine, mathematically speaking. But from an implementation standpoint, I wonder why one would do that. The logarithm that should be the fastest and the most precise one to approximate by a cpu should be the one to base two. In fact if one already has a floating point representation, it should be almost ridiculously easy to compute from the exponent. I suppose it's probably a good idea to use primitive functions for the harder cases to get some speed-up. What I don't see is why the choice seems to have been an /xor/ instead of an /and/. I am by absolutely no means an expert on these things, so I am probably missing something here. Is there actually a good reason for this choice? For example will ghc optimize such logarithms anyway? Cheers, MarLinn