> Message: 29 > Date: Sat, 6 Nov 2010 13:22:10 +0100 > From: Roel van Dijk <vandijk.r...@gmail.com> > Subject: [Haskell-cafe] hmatrix's fitModel function crashes ghc(i) > To: Haskell Caf? <haskell-cafe@haskell.org> > Message-ID: > <aanlktim5egsl_bz+ruv-=d-z3db65sc8o=ckqltcy...@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Hello, > > I would like to use hmatrix to do some function fitting with the > Levenberg Marquardt algorithm. As an example I would like to fit the > very simple function "f x = a*x + b" on some data points. The problem > is that executing the 'fitModel' function crashes GHC(i) with a > segmentation fault. This makes debugging difficult. Can anyone spot > what I am doing wrong? Given all the lists of Double's it seems very > easy to make an error regarding the number of arguments with the model > function or the derivative. > > Try to evaluate the 'test' function in the small program listed below. > I would expect an output of [1, 0] (y = 1*x + 0) instead of a > segmentation fault. > > Relevant versions: > - hmatrix-0.10.0.0 > - gsl-1.14 > - ghc-6.12.3 (64 bit) > > Is that the 64 bit Linux ghc?
I think the problem is with the GSL random number generation through GHCi. Try: > module Test where > > Import Numeric.Container(RandDist,randomVector) > > seed = 0 > size = 100 > > main = putStrLn $ show $ randomVector seed Gaussian size This should work when compiled with `ghc --make` and crash when invoked in `ghci`. I think the problem is with linking static data in GHCi on x86_64. Hope this helps. I seem to recall there might be a ghc trac ticket related to this but a quick search turned up nothing. Cheers, Vivian
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