From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jean-Max Redonnet <jmax.redonnet@meca.insa-tlse.fr>
To: gsl-discuss@sourceware.cygnus.com
Subject: 3 points from a new user of gsl
Date: Wed, 19 Dec 2001 13:20:00 -0000
Message-id: <01061516251601.22198@lgmt-fab5.ups-tlse.fr>
X-SW-Source: 2001/msg00218.html

Hi,

I'm a new user of gsl. I plan to use it for managing with vectors and 
matrices and multidimensional root finding.
Here is my first impression on this library (be indulgent, i'm not a great 
hacker,  just a phD in mechanical engineering needing free tools to solve its 
problems).

I'm using version 0.7 on Mandrake 8.0.
Install with rpm package is ok. Good job.
Just a small problem
$ /usr/bin/gsl-config --libs
returns
-L/usr/lib -lgsl -lm
This not include -lblas that might be useful sometines. Is it normal ?

Multidimensional root finding :
works fine especially with newton algorithm (as expected).
just a suggestion : It would be nice sometimes to be able to bound each 
variable. I've not find an easy way to do this in current release. Although 
this may help the algorithm to find the "right" solution. Is it possible ? Is 
it reasonnable to imagine this will be possible in future releases?

Vectors and matrices
I've not found any function to get the norm of a vector, so I've writed my 
own one, but I think this may be useful to include this feture in future 
release. What about this suggestion?
Here is my code to do this - Need improvements (especially to manage 
infinities)

double
vector_norm(gsl_vector *v, int n)
{
  int i;
  double tmp = 0;
  
  for(i = 0; i < v->size; i++)
    {
      tmp += pow(gsl_vector_get (v, i), n);
    }
  
  return sqrt(tmp);
}

Hope this points are in scope of this mailing list.

Jean-Max Redonnet