From: ara.t.howard@...
Date: 2006-05-07T08:12:34+09:00
Subject: Re: Numerical Ruby - Segmentation faults, GSL trouble

On Sun, 7 May 2006 Nuralanur@aol.com wrote:

> Dear all,
>
> I have to determine the minima of a multiparameter  mathematical function
> numerically.
> I try to use the simplex method, as implemented in Ruby-Gsl, to do  this.
>
> Below is some code from an example as given in the documentation of  Ruby/Gsl.
> However, when I run this on Cygwin (Windows XP), I get a segmentation  fault
> from the line where the parameters are set, whereas in Fedora, I am not
> allowed
> to allocate even the function to minimize.
>
> Has anybody had this problem before ? Has anybody some self-written  code
> for multidimensional minimization (preferably simplex method)?
>
> Thank you very much in advance,
>
> Best regards
>
> Axel

as to your first question, here are the results of running your code on my
machine:

   jib:~ > ruby a.rb
       1  6.500e+00  5.000e+00 f() = 512.500 size = 1.082
       2  5.250e+00  4.000e+00 f() = 290.625 size = 1.372
       3  5.250e+00  4.000e+00 f() = 290.625 size = 1.372
       4  5.500e+00  1.000e+00 f() = 252.500 size = 1.372
       5  2.625e+00  3.500e+00 f() = 101.406 size = 1.823
       6  2.625e+00  3.500e+00 f() = 101.406 size = 1.823
       7  0.000e+00  3.000e+00 f() =  60.000 size = 1.823
       8  2.094e+00  1.875e+00 f() =  42.275 size = 1.303
       9  2.094e+00  1.875e+00 f() =  42.275 size = 1.303
      10  2.578e-01  1.906e+00 f() =  35.684 size = 1.026
      11  5.879e-01  2.445e+00 f() =  35.664 size = 0.804
      12  1.258e+00  2.025e+00 f() =  30.680 size = 0.467
      13  1.258e+00  2.025e+00 f() =  30.680 size = 0.356
      14  1.093e+00  1.849e+00 f() =  30.539 size = 0.285
      15  8.830e-01  2.004e+00 f() =  30.137 size = 0.168
      16  8.830e-01  2.004e+00 f() =  30.137 size = 0.123
      17  9.582e-01  2.060e+00 f() =  30.090 size = 0.100
      18  1.022e+00  2.004e+00 f() =  30.005 size = 0.061
      19  1.022e+00  2.004e+00 f() =  30.005 size = 0.042
      20  1.022e+00  2.004e+00 f() =  30.005 size = 0.042
      21  1.022e+00  2.004e+00 f() =  30.005 size = 0.027
      22  1.022e+00  2.004e+00 f() =  30.005 size = 0.021
      23  9.920e-01  1.997e+00 f() =  30.001 size = 0.015
      24  9.920e-01  1.997e+00 f() =  30.001 size = 0.013
   converged to minimum at
      25  9.920e-01  1.997e+00 f() =  30.001 size = 0.008


your code was 100% un-modified.  so i think your install isn't good.  i just
installed the latest gsl, plotutils, and rb-gsl using

   export prefix=/dmsp/reference/
   export LD_RUN_PATH=$prefix/lib
   export LD_LIBRARY_PATH=$prefix/lib

   for gsl       : ./configure --prefix=$prefix && make && make install
   for plotutils : ./configure --prefix=$prefix && make && make install
   for rb-gsl    : for w in config setup install;do ruby setup.rb $w;done

eg.  nothing special at all.

so, sorry to say, it looks like you install is fubar.  btw.  my platform is

   jib:~ > uname -srm && cat /etc/redhat-release && ruby -v
   Linux 2.4.21-40.ELsmp i686
   Red Hat Enterprise Linux WS release 3 (Taroon Update 7)
   ruby 1.8.1 (2003-12-25) [i686-linux]


so, while it's not fedora, i'd be very suprised if it didn't work there too.

regards.


-a
-- 
be kind whenever possible... it is always possible.
- h.h. the 14th dali lama