My thoughts on what's written so far are different from Ondrej's. I am less excited by physics applications and more excited by the tools necessary to enable the expression of physics applications. The extent to which a domain specific project like this can be broken into a generally applicable component (some mathy or algorithmic bit) and a domain specific application (some physics thing) is good. This increases the applicability and relevance of a summer project to a wider audience.
On Thu, Mar 20, 2014 at 11:25 AM, Ondřej Čertík <[email protected]>wrote: > On Thu, Mar 20, 2014 at 12:17 PM, Ondřej Čertík <[email protected]> > wrote: > > Hi Peter, > > > > I read through your ideas. First of all, I started SymPy as a > > theoretical physics student myself, > > and I wanted to automate the General Relativity as well as high energy > > QFT calculations. I am still > > very interested in that, but there are a lot of tough problems and > > parts that need to be in place. > > > > You need to be able to do integrals, handle potentially large > > formulas, tensor manipulation and simplification > > (e.g. gamma matrices), and so on. It's not easy at all, but we've done > > a long progress since the time I started > > SymPy in 2007 or so. Most of these things are in place, in some form. > > In order to efficiently handle very large > > expressions, I started developing CSymPy about half a year ago > > (https://github.com/certik/csympy), this > > will come very handy as well for these applications. > > > > The best way to get some ideas of what can be done is to look into > > existing packages, they are pretty much > > all in Mathematica. In fact, most theoretical physicist just use > > Mathematica. And let's be frank, it's currently the > > best if you just care about getting the results. There is also GiNaC > > (http://www.ginac.de/) that can be used for some of the > > high energy stuff, but CSymPy can now do pretty similar things, > > sometimes faster. So there is: > > > > http://www.feyncalc.org/ > > > > there are all these various things people wrote for Mathematica: > > > > @article{huber2012crasydse, > > title={CrasyDSE: A framework for solving Dyson--Schwinger equations}, > > author={Huber, Markus Q and Mitter, Mario}, > > journal={Computer Physics Communications}, > > volume={183}, > > number={11}, > > pages={2441--2457}, > > year={2012}, > > publisher={Elsevier} > > } > > > > @article{huber2012algorithmic, > > title={Algorithmic derivation of functional renormalization group > > equations and Dyson--Schwinger equations}, > > author={Huber, Markus Q and Braun, Jens}, > > journal={Computer Physics Communications}, > > volume={183}, > > number={6}, > > pages={1290--1320}, > > year={2012}, > > publisher={Elsevier} > > } > > > > But the advantage of SymPy is that the whole stack is opensource, and > > SymPy is just a library, so it better integrates > > with things like IPython Notebook and you can create the whole > > application in it. For example, the physics.quantum > > module has some good stuff, that plays together much better than > > packages in Mathematica. Another great application is PyDy. > > > > So it would be really nice to have the project that you describe. You > > should have a look at work done by Francesco Bonazzi > > regarding the gamma matrices: > > > > https://github.com/Upabjojr > > https://github.com/sympy/sympy/pull/2601 > > > > He has lots of PRs, closed and open. It's nontrivial. And those are > > just the gamma matrices. I think Francesco's goal > > could be summarized by your proposal, and he's done many months worth > > of work on it already. So the scope is just huge. > > So there is plenty of things that could be done for the summer. > > > > One of the things is for example just the Feynman diagrams generator > > for various Lagrangians. I am sure there must be some > > packages that do that, but it'd be nice to integrate this with SymPy > > and create nice IPython Notebooks that generate all the correct > > diagrams, for example from Peskin & Schroeder. This will be good for > > I.e. this would involve some classes for representation of Feynman > diagrams, > that would also know how to nicely visualize themselves in the IPython > Notebook, > and then code that generates them for various interactions. > And so on. > > For other ideas, I have some derivations of various things here: > > http://theoretical-physics.net/dev/src/quantum/qft.html#standard-model > > that could be automated. For example one can reformulate the problem using > Green's functions and so on. > > Ondrej > > > pedagogical reasons, as well as computations. In general, > > good applications in my opinion are providing automatic symbolic > > solutions to various exercises from books. > > > > Another thing is of course Regularization and Renormalization. > > > > I would suggest you to figure out something, that can be finished > > during a summer and that would provide something useful, > > on it's own. So that you can create nice examples out of it. Then you > > can continue working on some other things after the summer. > > > > Ondrej > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CADDwiVCdh9JHMZ%3DQeUMK1-xrcXhjOY4JraWcs5OmnrzsJnZRZg%40mail.gmail.com > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. 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