The original rangemin project was my first Haskell package, and definitely my first attempt at super-advanced algorithms work in Haskell. (I here define "super-advanced" as "not in MIT OpenCourseWare undergraduate algorithms lecture notes from any year.") Here's the problem: Suppose we have an array of length n. Preprocess the array in O(n) time such that we can look up the minimum element of any slice in the array in O(1) time. Coming back to this project after two years, and especially rewriting the approach with the vector package, was *spectacularly* fun. rangemin-2.0http://hackage.haskell.org/package/rangeminis now on Hackage, with a new API as well. The constant factor on the O(n) preprocessing is, based on criterion benchmarks, 88 milliseconds per million elements, on my 2.5GHz Ubuntu laptop, with GHC HEAD and -O2 -fvia-c -optc-O3. I've spent the past three days unsuccessfully trying to get the LLVM backend to work, because this algorithm has a *lot* of the sort of tight loops that LLVM excels at. Unfortunately, I haven't been able to install the LLVM backend, which is very disappointing. That said, GHC with the C backend is about 10x slower than an optimized C++ implementation, which is all right considering that the algorithm plays so much to C++'s strengths. (If anybody has LLVM working and would be willing to help, I'd massively appreciate it if you could benchmark both the C++ implementation -- not mine, but included in a tarball inside the rangemin distribution package -- and my implementation, with LLVM -O2. Benchmarking code is herehttp://hpaste.org/fastcgi/hpaste.fcgi/view?id=25309#a25309 .) Louis Wasserman wasserman.louis@gmail.com http://profiles.google.com/wasserman.louis