On Tue, 2008-10-07 at 23:01 +0200, Thomas Treichl wrote: > Wang Long schrieb: > > Hi, > > > > When I was running this in octave: > > > > t_in = [0 0.05 0.13 0.19]; > > [t_out, y] = ode45 (@(t,x) x, t_in, 1); > > > > I got t_out=[0.00000 0.05000 0.10000 0.15000 0.19000]. While the > > length of t_in is 4, I found that of t_out is 5 instead of 4. However > > the length of t_in and t_out should be identical. This bug also exists > > in ode23, ode54, ode78, etc. > > > > I'm using octave on Ubuntu, and the file "ode45.m" belongs to the > > package "octave-odepkg" version 0.6.0-1. > > > > Any ideas? Thank you all. > > > > Regards, > > Wang Long > > Hi Wang, > > please change line number 406 (file ode45.m) originally from > > vstepsize = vslot(1,vcntloop-1) - vslot(1,vcntloop-2); > > into > > vstepsize = vslot(vcntloop) - vslot(vcntloop-1); > > Does this fix the ode45 problem for the 0.6.0 release of the package? At > least > it seems to fix the problem for the latest sources and the next package that > will become available. > > Thomas
Hi Thomas, Thank you very much in helping me with this problem! The solution in your email solved the problem I mentioned before, but when I tried some other t_in's, for example, t_in_2=[0.00 0.10 0.23 0.38 0.63 1.21 1.97]; t_in_3=[0.00 0.03 0.05 0.11 0.17 0.25 0.38 0.47 0.68 0.91 1.38 1.98]; it seems that the same problem comes out again in the 0.6.0 release of odepkg :( I examined the improper t_out's, and found that every element in them is identical to t_in's, respectively, except those at ``t_out(end-1)'', which is created by ode45. Therefore, can we simply make ode45 check the length of t_out, and delete certain elements of t_out (and ``y'', of course) if the length of t_out is larger than t_in? Thanks! Regards, Wang Long ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Octave-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/octave-dev
