On Mar 19, 2011, at 2:22 AM, Tim Lahey wrote: > On 03-19-2011, at 4:07 AM, Aaron S. Meurer wrote: > >> On Mar 19, 2011, at 2:01 AM, Tim Lahey wrote: >> >>> On 03-19-2011, at 3:48 AM, Aaron S. Meurer wrote: >>> >>>> On Mar 19, 2011, at 12:30 AM, Tim Lahey wrote: >>>> >>>>> >>>>> My thought would be to create a new module for calculus of variations >>>>> (probably called calcvar) and put it under that. That way, more can be >>>>> added to it and I can't really see a current module (other than possibly >>>>> physics) that it fits in. I've forked the main repository, so I'll see >>>>> about doing this. >>>>> >>>> >>>> What other things would eventually go in the module? >>>> >>> >>> Well, there are various tests that could go in the module. That's what's in >>> the Maple Calculus of Variations package. What I'd like to see is the >>> ability to take a variation. I've implemented something simple along these >>> lines in Maple already. It's not particularly robust at the moment though. >> >> I'm not sure if I understand what you mean by "tests". > > There are various functions to characterize the functionals. Maple's calculus > of variations help is, > > http://www.maplesoft.com/support/help/Maple/view.aspx?path=VariationalCalculus > > The package has a test to see if the integrand is convex. There are other > similar tests that could be there but aren't. There are also other functions > similar to the Euler-Lagrange that could be included (e.g., Jacobi, > Weierstrass). I'm not particularly interested in these, but others may be. > >> >>> >>>> It definitely shouldn't go in physics, since calculus of variations is >>>> useful to more than just physics! >>> >>> I agree. The only other place it kind of fits is the integrals module, but >>> that's not really right since the Euler-Lagrange equation is a differential >>> equation, not an integral. I find the naming of that module somewhat >>> unfortunate since I'd rather see a calculus module with integrals, ODEs, >>> and PDEs in it. If that was the case, I'd put the calculus of variations >>> stuff in there. >> >> It actually makes sense to me to have all the solvers together (solvers, >> ode, pde, recur, etc.). >> >> integrals does indeed deserve its own module, because it will get very large >> as more and more of the integration algorithm is implemented. >> > > It's more that I think integrals should have been called calculus instead.
Well, integrals is just the integration part of calculus, and there is enough of that alone to justify a separate module (trust me). > >> Anyway, where do you think it should go given the way things are? I don't >> have any ideas. >> > > Right now, it doesn't really fit anywhere, that's why I think it should be a > new module. If we create a new "calculus" module then we could put the > calculus of variations stuff in there and tools to manipulate differential > equations that aren't strictly about solving DEs. Like Maple's DE and > PDEtools packages. Hmm. I'm not sure about this idea. It requires moving a lot of stuff around. Potentially, if this module could get quite large with a bunch of future enhancements, then it would make sense. I supposed that DEtools and PDEtools are quite large in Maple. Does anyone else have an opinion on this? Anyway, don't let this superficial discussion stop you from making your patch. Go ahead and add your function to a calcvar.py file somewhere (in a calculus directory if you like), and we will discuss it in the review. Aaron Meurer > > Cheers, > > Tim. > > --- > Tim Lahey > PhD Candidate, Systems Design Engineering > University of Waterloo > http://about.me/tjlahey > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
