I did not check the calculations, but... are you sure it's not a problem of valence (i.e. contravariant or covariant indices differ)?
We need a tensor-array data structure (i.e. an N-dimensional array with valence markings) to solve this kind of confusion. On Monday, 26 October 2015 12:18:04 UTC+1, Imran Ali wrote: > > It turns out that the Christoffel symbol of second kind found with > sympy.diffgeom was invalid. I will try to make a new post here for this > soon. > > On Saturday, October 24, 2015 at 9:11:28 PM UTC+2, Imran Ali wrote: >> >> I have made a geodesic solver using sympy.diffgeom and scipy.integrate. >> Currently I am having some issue with the solver. But the problem may be >> related to Scipy. I have posted a thread here : >> >> >> http://scicomp.stackexchange.com/questions/21103/numerical-solution-of-geodesic-differential-equations-with-python >> >> Will let you know how it turns out. >> >> On Monday, October 19, 2015 at 4:31:37 PM UTC+2, Ondřej Čertík wrote: >>> >>> On Mon, Oct 19, 2015 at 7:59 AM, Imran Ali <[email protected]> wrote: >>> > >>> > >>> > On Saturday, October 17, 2015 at 8:49:28 PM UTC+2, Francesco Bonazzi >>> wrote: >>> >> >>> >> >>> >> >>> >> On Saturday, 17 October 2015 17:52:38 UTC+2, Imran Ali wrote: >>> >>> >>> >>> >>> >>> But this result does not correspond to the hand calculations of >>> Thomas >>> >>> Moore : >>> >>> >>> >> >>> >> Do you know that unlike matrices tensors don't have defined >>> components? I >>> >> mean, you may vary their valence (i.e. raise and lower the indices), >>> and >>> >> you'll get different components. >>> >> >>> >> I did not verify it by hand, but I guess that if you raise the first >>> index >>> >> of Thomas Moore's Riemann tensor, you'll get the output by SymPy. >>> > >>> > >>> > Ah of course! He has calculated the covariant form of the >>> > Riemann-Christoffel tensor. >>> >>> >>> Perfect. Does everything work as expected then? >>> >>> If you find further possible problems, please let us know. >>> >>> 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/e336ecb1-f778-4f32-98c6-5830cc5a0a08%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
