W dniu wtorek, 6 maja 2014 10:40:51 UTC+2 użytkownik Mauro napisał: > > This is cool. Questions: > - I think the original dassl was limited to banded Jacobians but in this > implementation any (sparse)-Jacobian works, right? > As of yet there is no support for providing user defined jacobian or any sparsity information. But I plan to add it in the future as I will need it myself. At this point jacobian is assumed to be dense and it is computed numerically via finite differences.
> - Are there any of the good old licencing issues here? DASSL comes without > one. > I don't know about the licence of DASSL, but this is a reimplementation from scratch. I doubt that the general idea behind DASSL algorithm itself is licensed, although I cannot tell for sure. > > On Tuesday, May 6, 2014 9:21:39 AM UTC+1, Ivar Nesje wrote: >> >> I think a DAE solver would be a great fit for ODE.jl. Currently I think >> it will be best to develop it outside, until a few important cleanups is >> performed on the ODE solvers. The state of ODE.jl is between a breaking API >> discussion and implementation of that described API. It would be very nice >> if you could read some of the >> discussion<https://github.com/JuliaLang/ODE.jl/search?q=api&ref=cmdform&type=Issues> >> and >> documentation<https://github.com/JuliaLang/ODE.jl/blob/master/doc/api.md> >> and >> comment from your point of view. Some consensus has been reached, but there >> are still possible to argue for different solutions. >> >> Ivar >> >> kl. 10:02:40 UTC+2 tirsdag 6. mai 2014 skrev Alex følgende: >>> >>> Or submit a PR for including it in ODE.jl :-) >>> >>> Best, >>> >>> Alex. >>> >>> >>> On Tuesday, 6 May 2014 09:57:34 UTC+2, Viral Shah wrote: >>>> >>>> It's great to see a DASSL implementation in Julia! Do register it with >>>> METADATA. >>>> >>>> -viral >>>> >>>> On Tuesday, May 6, 2014 12:41:20 PM UTC+5:30, Paweł Biernat wrote: >>>>> >>>>> For the last several weeks I have been implementing [1] a DASSL >>>>> algorithm in Julia. The DASSL algorithm was developed by Linda >>>>> Petzold in late 80s to solve Differential Algebraic Equations (DAE) >>>>> and its Fortran 77 implementation is one of the most popular DAE >>>>> solvers. My implementation in Julia bases mainly on a book [3] and >>>>> partly on the source of the original implementation [2] (mostly in >>>>> places where the book was ambiguous). I tried to mimic the behavior >>>>> of the original implementation as much as I could but my code is not >>>>> in a one to one correspondence with the original (I aimed at >>>>> readability of the algorithm), so don't be surprised if you get >>>>> slightly different results from both versions. >>>>> >>>>> This is my first larger project in Julia so don't expect high end >>>>> quality or performance, but I tested my implementation for convergence >>>>> on various simple index-0 and index-1 problems and it works just >>>>> fine. That said, I am open to any critique and suggestions, and any >>>>> help with improving the code. Ultimately, I would like to see this >>>>> code merged into the ODE.jl library, if the maintainers of the latter >>>>> allow it. >>>>> >>>>> [1] https://github.com/pwl/dassl.jl >>>>> [2] http://www.netlib.org/ode/ddassl.f >>>>> [3] "Numerical Solution of Initial'Value Problems in >>>>> Differential-Algebraic Equations" K. E. Brenan, S. L. Campbell, L. R. >>>>> Petzold >>>>> >>>>>
