lsode

[John W. Eaton]

On 15-Jun-1999, Daniel Tourde <address@hidden> wrote:

| I'm running computation of the kind x_dot = f(x). 
| I was used to run Octave 2.0.13 on a Libc1 Linux 2.0.x machine. Now I
| use Octave 2.0.14 on RedHat 6.0 (Glibc2.1). I use the function lsode an
| now I obtain the following message which never appeared before :
| 
| error: giving up after more than 100000 steps attempted in lsode
| error: evaluating index expression near line 274, column 19
| error: evaluating assignment expression near line 274, column 17
| 
| Does anyone has a clue of how I could turn around this problem ?

In 2.0.14, it was supposed to be possible to set the step limit with
something like

  lsode_options ("step limit", 1e6)

but a stupid error prevented it from working.  The problem will be
fixed in 2.0.15.  If you need a fix sooner than that, here is a patch
to try.  Your line numbers will most likely be different.

--- octave-2.0.14/src/lsode.cc  Thu Oct  8 22:29:11 1998
+++ lsode.cc    Fri Apr 23 15:20:19 1999
@@ -227,7 +243,7 @@
 
   { "step limit",
     { "step", "limit", 0, },
-    { 1, 0, 0, }, 1,
+    { 1, 0, 0, 0, }, 1,
     0, &LSODE_options::set_step_limit,
     0, &LSODE_options::step_limit, },
 

Another option is to break up your integration into smaller parts that
can each be completed in less than 100000 steps...

jwe



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