public inbox for gsl-discuss@sourceware.org
 help / color / mirror / Atom feed
From: Philippe Huber <huberph@infomaniak.ch>
To: gsl-discuss@sources.redhat.com
Subject: Problem with matrices bigger than 2x2 using gsl_linalg_LU_invert
Date: Mon, 19 Aug 2002 03:42:00 -0000	[thread overview]
Message-ID: <001101c2476d$18a7c250$7e28c281@osiris> (raw)

Hi all,
 
First of all, thank you for having created such a great library. I have
a small problem with gsl_linalg_LU_invert. I am using a 4x4 matrix which
is not singular. I made a LU decomposition using gsl_linalg_LU_decomp.
Then, I send it to gsl_linalg_LU_invert and it crashes. I tried with a
2x2 matrix and it works perfectly well. When debugging, I saw that at
the third iteration (i=2) of 
  for (i = 0; i < n; i++)
    {
      gsl_vector_view c = gsl_matrix_column (inverse, i);
      int status_i = gsl_linalg_LU_svx (LU, p, &(c.vector));
 
      if (status_i)
            status = status_i;
    }
inside decomp, c.vector.size=4 but, in invert, the side of x (which
should be c.vector.size) is 1239492! I verified that the program also
crashes with a 3x3 matrix. Is it a bug or did I make something wrong.
Please apologize if I don't send my code, it is well too big.
 
Thank you
 
Philippe


             reply	other threads:[~2002-08-19 10:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-08-19  3:42 Philippe Huber [this message]
2002-08-19 11:32 ` Brian Gough
2002-08-19 12:39   ` RE : " Philippe Huber

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='001101c2476d$18a7c250$7e28c281@osiris' \
    --to=huberph@infomaniak.ch \
    --cc=gsl-discuss@sources.redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).