[SciPy-dev] dae solvers

[Nils Wagner]

On Fri, 29 Aug 2008 11:07:41 +0200
  "Benny Malengier" <benny.malengier@gmail.com> wrote:
> I created a patch to scipy to add support for dae 
>solvers:
>    http://www.scipy.org/scipy/scipy/ticket/730
> 
> The backend I included is the netlib ddaspk.f solver.
> 

You might be interested in

http://www.ma.ic.ac.uk/~jcash/IVP_software/readme.html

Cheers,
           Nils


> I chose for this as I need to solve large systems and I 
>want to keep the
> speed of fortran with a minimum of overhead in python.
> It should be possible to add quickly the backend lsodi 
>based on patch
> http://www.scipy.org/scipy/scipy/ticket/615 . Adding a 
>backend to the ida
> solver in sundials should also be possible based on the 
>pysundials package
> (advantage over pysundials would only be a single api 
>definition )
> Extension to add support of Krylov within ddaspk should 
>also be easy with
> some overloading.
> 
> Well, I can improve this (extra backend, ...) if it is 
>considered for
> inclusion in scipy, otherwise it is just a way of 
>sharing it in the hope the
> next person doesn't have to reinvent it all again.
> 
> Greetings,
> Benny
> 
> 2008/8/25 Rob Clewley <rob.clewley@gmail.com>
> 
>> On Sun, Aug 24, 2008 at 8:18 AM, Benny Malengier
>> <benny.malengier@gmail.com> wrote:
>>
>> > Guess I should have googled a bit longer.
>>
>> Well, maybe a bit longer still :) There have been a 
>>couple of other
>> attempts, too. For instance, you might get some joy from 
>>the wrapped
>> version of Radau, which has a lighter interface and is 
>>part of a more
>> python-oriented environment.
>>
>> > As this pysundials is there, I do think it should be 
>>integrated somehow
>> in
>> > scipy. What use of ode class and odepack in scipy 
>>which interface old
>> > vode/lsode fortran progs when pysundials exists that 
>>interfaces sundials
>> and
>> > like that the new cvode and ida solvers?
>> > So perhaps ode.py should obtain a backend to that?  Or 
>>should scipy just
>> no
>> > longer offer ode solvers...
>>
>> There has been some discussion about ode solvers in 
>>scipy recently,
>> but it didn't come to much. People are still busy 
>>arguing over how to
>> represent matrices properly, let alone getting in to how 
>>dynamical
>> systems should be supported. Someone tried starting a 
>>new interface to
>> the existing ode solvers in scipy recently, but I don't 
>>know how
>> that's getting along. I think it's called pyode and on 
>>google code.
>>
>> > Well, I'm not a scipy dev, just my 2 cents. It always 
>>amazes me how many
>> > duplication is going on. I'll investigate my options 
>>furter and make up
>> my
>> > mind next week on how to proceed.
>>
>> I mostly agree, but it's tricky to talk about 
>>duplication. Users in
>> different fields want different things from their 
>>packages, and have
>> different expectations about how many dependencies 
>>they're willing to
>> tolerate, how much of a GUI is supported, what kinds of 
>>application or
>> data formats are supported, etc. So there end up being 
>>some conscious
>> attempts to do similar things somewhat differently. And 
>>so that's not
>> necessarily a bad thing.
>>
>> -Rob
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