[SciPy-user] Moving Grid in SciPy

Lorenzo Isella lorenzo.isella@gmail....
Fri Jul 6 09:29:00 CDT 2007


Dear All,
A question which I hope will not look too general for this mailing list.
I do quite a lot of work of population equations, which generally are
a set of 1st order ODE's:

dn_k/dt=f_k(t,....)    for k=1....N

where n_k is the population of the k-th level.
Now, in my specific problem the levels at low kappa get progressively
empty as the population moves toward high k.
This means that, after a certain time, formulating the problem as a
"fixed" (hope you understand what I mean here) set of ODE's, I am
waisting cpu time on empty levels.  It would be better to "recycle"
them e.g. by sending levels with k=1,2 into levels with
k=N+1, N+2 and so on.
This method is called "moving grid" and has been used for quite a
while in my field, but before diving into the (maybe too) abundant
literature, I would like to find out if there is such a tool already
implemented in Python or SciPy directly or whose implementation is
rather trivial.
At the moment I am using integrate.odeint for my calculations (of
course still on a fixed grid).
Any suggestions are really welcome.
Many thanks

Lorenzo


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