John B. Thoo schrieb:
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.
---John.
Good question, I would say that you have a tricky problem and the
solver gets into trouble ;) For a quick workaround: what happens if
you use another solver like ode78? What about ode5r? I tried your
example but get
octave-3.2.0:10> run_twoway
error: `heaviside' undefined near line 4 column 18
error: called from:
error: /Users/Thomas/tmp/thoo/TwoWay/make_k.m at line 4, column 14
error: /Users/Thomas/tmp/thoo/TwoWay/run_twoway.m at line 20,
column 3
Best regards
Thomas