Re: 1D PDE solver for Octave

[Bill Greene]

Thanks for taking the time to reply although I am disappointed

that you didn't address any of my issues.

I am using the C API to ida; my code is written in C++.

My code is currently using a simple linear interpolation in the

spatial dimension and then using ida to solve the resulting system

of ODE. I intend to improve the spatial discretization in the future

but the current implementation could certainly be considered "inferior"

to pdepe. I'm not trying to duplicate pdepe-- just support the same

problem class and the command line interface as closely as possible.

I should say one more thing about Sundials ida. The latest version of 

ida is only just "adequate" to support my current implementation,

mainly because its sparse matrix support is rather rudimentary. I am

hoping they will improve ida in this area and expect that for the

foreseeable future I'll want to be using the very latest ida release.

I am aware of the ongoing Octave ode15s work; I alluded to that in my original

message.

I would be happy for anyone to try the current code. At this point, I

consider it to be solid beta-quality code.

Thanks.

Bill

On Thu, Jun 30, 2016 at 8:31 AM, Carlo De Falco <address@hidden> wrote:

On 29 Jun 2016, at 19:29, Bill Greene <address@hidden> wrote:

> The function is implemented as a C++ mex file. It depends very
> heavily on the Sundials ida ODE solver, somewhat less heavily
> on the Eigen C++ matrix class library, and a couple of libraries
> from Boost.
>

Hi,

Thanks for your interest in contributing to Octave!

I'd like to know more about what you are doing in order
to provide more informed suggestions.

I'm not sure what you intend by "C++ MEX file" MEX is a C API,
Octave has its own C++ API.

You say you are relying on sundias IDA, are you using
IDA's own C API or the MEX interface?

There is another ongoing project to implement matlab
compatible ode15s and ode15i via and interface to sundias IDA [1,2].

So in the near future there will be also an oct-file interface to
IDA which based on initial benchamarking is substantially
faster than the MEX file interface distributed with sundials.

I am also curious about what algorithm does your code exactly
implement because IDA and PDEPE are based on completely different
mathematical methods so I'm not sure what you are actually doing ...

c.


[1] http://gsoc2016ode15s.blogspot.it/
[2] https://bitbucket.org/Francesco_Faccio/octave/