On Wed, Mar 18, 2009 at 3:19 PM, Alan Bromborsky <[email protected]> wrote: > > Ondrej Certik wrote: >> Hi Comer, >> >> On Wed, Mar 18, 2009 at 9:17 AM, [email protected] >> <[email protected]> wrote: >> >>> I am interested in using Sympy but see on the web page that >>> implementing tensors is rather low on the list of interested >>> additional features. Can the developers give some indication as to >>> when tensor algebra will be added to Sympy? >>> >> >> When we find someone interested in pushing this forward. If you'd be >> interested, play with some very preliminary code here: >> >> $ python examples/advanced/relativity.py >> [...] >> solve the Einstein's equations: >> ⎛ C₂⎞ >> λ(r) = -log⎜C₁ + ──⎟ >> ⎝ r ⎠ >> metric: >> ⎡ C₂ ⎤ >> ⎢-C₁ - ── 0 0 0 ⎥ >> ⎢ r ⎥ >> ⎢ ⎥ >> ⎢ 1 ⎥ >> ⎢ 0 ─────── 0 0 ⎥ >> ⎢ C₂ ⎥ >> ⎢ C₁ + ── ⎥ >> ⎢ r ⎥ >> ⎢ ⎥ >> ⎢ 2 ⎥ >> ⎢ 0 0 r 0 ⎥ >> ⎢ ⎥ >> ⎢ 2 2 ⎥ >> ⎣ 0 0 0 r ⋅sin (θ)⎦ >> >> >> It allows you to calculate the Schwarzschild metrics pretty easily. >> However, it'd be nice to polish the classes in there, and make it part >> of sympy, write tests for it, more examples etc. If you'd be >> interested in helping out, I fully support it. >> >> >>> I do general relativity >>> and thus need tensor capability. >>> >> >> Yes, I would love to do more advanced stuff in GR as well with sympy. >> >> Ondrej >> >> > >> >> > If you get the latest snapshot of sympy: > > git clone git://git.sympy.org/sympy.git > > There is an extensive geometric algebra/calculus module (numpy required) with > attached documentation > (python-sphinx and dvipng required). The use of geometric algebra in general > relativity is documented in > "Geometric Algebra for Physicists" by Doran and Lasenby (Cambridge University > Press). The main website > is http://www.mrao.cam.ac.uk/~clifford/. One of the examples in the book is > a one line expression of > the curvature tensor for a rotating black hole using geometric algebra.
Thanks Alan. Alternatively, if you live around Nevada/Reno, you can come to my place and we can get implemented what you need like we did with Luke: http://ondrejcertik.blogspot.com/2009/03/newtonian-mechanics-with-sympy.html Ondrej --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
