[fem-fenics] Function evaluation

[Eugenio Gianniti]

Dear Marco,

you can find on the hg repository [1] my latest work on the function evaluation feature and in my blog a post [2] about it. Note that the interface change highlighted in the post has already been implemented, later I will write a post to document it and show how it can be used.

I have a couple of doubts about which I could use some advice. The first one concerns the handling of output arguments: currently the function evaluation stops complaining about their wrong number if they are not as much as the values the function takes. Probably it is too strict, but I do not know if there is an expected behaviour for Octave functions in this aspect or any guidelines to follow.

My second doubt is related to the association of fem-fenics functions with function handles. I tried to go through the code base in order to understand what to do, but I cannot quite get it. I expect that the function class should inherit from octave_function, but it is not enough, because if I type "handle = @function" Octave complains about not finding a function or a method to attach to the handle. Basically I grasp that there is some preparation made when a regular function is loaded, probably meant to make it available in the symbol table, that the fem-fenics function class lacks. To be honest, I do not even know if it is possible for something to be at the same time both a function and a variable, which is what I try to accomplish. If you think it is something feasible, I would need an explanation, otherwise I look forward to suggestions on an alternative approach.

Regards,

Eugenio

[1] http://hg.octave.org/fem-fenics-eugenio/

[2] http://gsoc2014-eg123.blogspot.it/2014/06/function-evaluation.html