[SciPy-user] PyDSTool and SciPy (integrators)
Gabriel Gellner
ggellner at uoguelph.ca
Thu Apr 17 22:35:09 EDT 2008
> > I think the right return format depends what people want from the
> > solution. I see two major kinds of problem one might use an ODE solver
> > for:
> >
> > * Integrate out to some stopping point and give the values of
> > dependent and independent variable there.
> > * Integrate out to some stopping point and give back a representation
> > of the solution.
> >
> > (The first case can in principle be obtained by evaluating the second
> > at the endpoint, but at the cost of replacing O(1) space by O(n)
> > space.)
>
> I personally do not find the former very useful, as I almost always
> want to know something about the intermediate points. My understanding
> is the dopri and radau integrators inherently return the whole
> solution, so maybe an additional calling option supporting the former
> usage could just throw everything out but the last point before the
> whole solution gets copied into a numpy object.
>
I don't think this is true, as far as I understand the dopri codes don't save
anymore than the runge kutta method needs which is a single step, it is up to the
user supplied callback to save any information, so I think you could just
write a callback that after each point checks if the time is the terminal time
and only save that point.
I will try a proof of concept of this.
Gabriel
More information about the SciPy-User
mailing list