Re: ode45 gives solution in the "Dark Side," but not in Octave

[John B. Thoo]

On Sep 1, 2009, at 3:00 PM, John W. Eaton wrote:

> On  1-Sep-2009, John B. Thoo wrote:
>
> | Hi.  I have a question about using ode45 in Octave 3.2.2 (and OdePkg
> | on Mac OS X 10.4.11) vs. in the "Dark Side" 7.4.0 (R2007a) (on a
> | server ... Linux?).  My code can be found here at the moment:
> |
> | <http://ms.yccd.edu/~jb2/PickUp/twoway.zip>
> |
> | "run_twoway.m" executes the code.
> |
> | Both Octave and the Dark Side solve the problem (i.e., do not return
> | an error) to produce a solution  u,  and both give
> |
> |  > size (u)
> | ans =
> |
> |     8192    102
> |
> | However, while I can plot the solution in the Dark Side, in Octave I
> | can plot only the first four frames.  In fact, in Octave I get   
> NaN +
> | 0.00000i  from  u(:,5)  on.  Why is that?
> |
> | I would appreciate any hints.  Thanks.
>
> Have you tried using lsode in Octave instead of ode45 (which is not
> part of Octave, BTW).

I haven't tried lsode.  The reason for my using ode45 is my advisor  
uses the Dark Side only, and we need to run the same code.  Thanks.

---John.