On Wednesday, November 19, 2014 11:17:24 PM UTC+1, Jason Moore wrote: > > Sachin Joglekar developed the vector package this past summer. I was his > GSoC mentor on the project. You can check out this implemented of the > Cartesian coordinate system: > > https://github.com/sympy/sympy/blob/master/sympy/vector/coordsysrect.py >
In sympy.diffgeom coordinate systems are defined as instances of the CoordSystem class, once more coordinate systems are defined, the transformation rules are set using the *connect_to* method: In [1]: from sympy.diffgeom import * In [2]: r, theta, phi = symbols('r theta phi', positive=True) In [4]: M = Manifold('M', 3) In [5]: P = Patch('P', M) In [7]: rect = CoordSystem('rect', P, ['x', 'y', 'z']) In [8]: spherical = CoordSystem('spherical', P, ['r', 'theta', 'phi']) In [9]: spherical.connect_to(rect, [r, theta, phi], [r*sin(phi)*cos(theta), r*sin(phi)*sin(theta), r*cos(phi)], inverse=False) I put *inverse=False* in the last line, because SymPy's solvers are unable to reverse the spherical-to-rect transformation. Manifold and Patch are some boilerplate, Manifold specifies the space you're considering, while Patch is a connected subspace of the manifold. Patch is used because on some manifolds there does not exist a homeomorphism to a coordinate system (e.g. on the sphere). I think that some algorithmic code could be shared between the vector and the diffgeom modules. -- 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 sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. 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/7341823f-1172-4ecb-b322-f52f115d44f4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.