James worked with Featherstone's book "Rigid Body Dynamics Algorithms". But I think that the spatial vector implementation used in simbody may be a good thing to copy.
I also think that focusing on improving end-user use of the software is more bang for the buck and adding the Featherstone algorithm doesn't add much for general users. Jason moorepants.info +01 530-601-9791 On Mon, Feb 8, 2021 at 1:58 PM Sudeep Sidhu <sudeepmanilsi...@gmail.com> wrote: > > > On Mon, 8 Feb 2021, 18:24 Sudeep Sidhu, <sudeepmanilsi...@gmail.com> > wrote: > >> Jason, >> >> I would definitely like to work on physics mechanics/vectors project in >> this summer as physics has been my favourite subject and I'm really eager >> to learn more physics to code it and I think I can learn it myself while >> coding plus you could help me if I get stuck somewhere. >> >> So which would be better to implement first, spatial vector or >> Featherstone method? If possible can you please share notes or pdf link of >> related topic as it would be nice to have a headstart. >> > >> >> > I would really like to implement Spatial Vector in this year's GSoC . If > possible please share a link of a good source to read and learn more about > spatial vectors. > >> >> >> >> >>> >>> On Mon, Feb 8, 2021, 12:50 Jason Moore <moorepa...@gmail.com> wrote: >>> >>>> Sudeep, >>>> >>>> FeatherstoneMethod should not require any implementation of joints, I >>>> think it should work with knowledge of the rigid bodies and particles in a >>>> system and their relative kinematics. That would keep things general. I do >>>> think that a nice implementation of a spatial vector would provide the best >>>> foundation for building the Featherstone algorithm and allow it to work >>>> with the classes we have already established for describing the kinematics >>>> of a system. >>>> >>>> Jason >>>> moorepants.info >>>> +01 530-601-9791 >>>> >>>> >>>> On Mon, Feb 8, 2021 at 9:08 AM Sudeep Sidhu <sudeepmanilsi...@gmail.com> >>>> wrote: >>>> >>>>> Jason, >>>>> >>>>> I would like to work in this realm in this year's GSoC. >>>>> >>>>> I went through Sahil Shekhewat's and James Milam's (jbm950) previous >>>>> unmerged GSoC work and found out that(I may be wrong) *FeatherStoneMethod >>>>> *can't be added until we add fully working *JointsMethod* class and >>>>> implement *spatial vectors*. >>>>> >>>>> I would like to implement *Spatial Vectors* in this year's GSoC and >>>>> would like to discuss it further. >>>>> >>>>> Sudeep Sidhu >>>>> >>>>> >>>>> >>>>> >>>>>> On Sun, Feb 7, 2021 at 2:24 PM Jason Moore <moore...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> Sudeep, >>>>>>> >>>>>>> The topics related to sympy.physics.vector/mechanics are still >>>>>>> possibilities. I will have time to mentor this summer if someone wants >>>>>>> to >>>>>>> do projects in this realm. >>>>>>> >>>>>>> We have not updated the ideas page yet for this year so those could >>>>>>> be adjusted. Off the top of my head here are some things that I think >>>>>>> are >>>>>>> priorities: >>>>>>> >>>>>>> - Finish and enhance the work of Sahil Shekhewat so that models can >>>>>>> be built with body and joint specifications (unmerged GSOC work). >>>>>>> - Finish and enhance the work of James Milam (jbm950) that adds a >>>>>>> FeatherstoneMethod. This is one way to increase the computational >>>>>>> efficiency. One thing that is missing are nice implementations of >>>>>>> spatial >>>>>>> vectors and their operators. >>>>>>> - Finish and enhance the work of Nikhil Pappu. The Autolev parser >>>>>>> needs to be battle tested on some examples and bugs worked out. We need >>>>>>> the >>>>>>> tests in the private gitlab repo to actually be run by SymPy. (merged, >>>>>>> but >>>>>>> not polished GSOC work). >>>>>>> - The Linearizer class was updated by James Crist, but I think it is >>>>>>> effectively broken for more complex problems. This needs to be fixed >>>>>>> and we >>>>>>> need examples of it working for systems with holonomic and nonholonomic >>>>>>> constraints. >>>>>>> - Improve symbolic computational speed. Hard examples need to be >>>>>>> profiled and the Python implementations improved, work on the core >>>>>>> differentiation algorithms to maximize speed, and ensure that optional >>>>>>> dependencies on symengine function and help for hard problems. >>>>>>> - Develop a more comprehensive set of examples. I've started >>>>>>> creating more and migrating threse to the PyDy documentation: >>>>>>> https://pydy.readthedocs.io/en/latest/#examples. One barrier to >>>>>>> user adoption is the lack of examples that are clearly written that >>>>>>> cover >>>>>>> all types of dynamic systems. >>>>>>> - I've recently discovered that for some problems the resulting >>>>>>> symbolic equations are in a form that results in numerical error >>>>>>> accumulation in the arithmetic. This is problematic and figuring out >>>>>>> what >>>>>>> this issue is and remedying it would be a nice improvement. >>>>>>> - All of these PRs are hanging: >>>>>>> https://github.com/sympy/sympy/pulls?q=is%3Aopen+is%3Apr+label%3Aphysics.mechanics >>>>>>> and it would be nice to resolve them and get them merged. >>>>>>> - If work can be done on PyDy, as has in the past, there are several >>>>>>> things there too 1) support DAEs, 2) improve the visualizer in a number >>>>>>> of >>>>>>> ways, 3) migrate examples to jupyter-sphinx, etc. >>>>>>> >>>>>>> At this point, I'm generally in disfavor of proposing any new >>>>>>> features or extensions to the library over fixing and improving what we >>>>>>> already have. As you can see, we have several GSoC projects that were >>>>>>> not >>>>>>> fully polished off or were not merged at all. >>>>>>> >>>>>>> Jason >>>>>>> moorepants.info >>>>>>> +01 530-601-9791 <(530)%20601-9791> >>>>>>> >>>>>>> -- >>>>>>> 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+un...@googlegroups.com. >>>>>>> >>>>>> To view this discussion on the web visit >>>>>>> https://groups.google.com/d/msgid/sympy/CAP7f1AgguJTXrTiNpZVS-oe9-jT8BjeSqRiJRPCmbhj4mC4b5A%40mail.gmail.com >>>>>>> <https://groups.google.com/d/msgid/sympy/CAP7f1AgguJTXrTiNpZVS-oe9-jT8BjeSqRiJRPCmbhj4mC4b5A%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>> . >>>>>>> >>>>>> -- >>>>> 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 view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/sympy/46e97251-1908-4bc4-af73-20faba189babn%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/sympy/46e97251-1908-4bc4-af73-20faba189babn%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> 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 view this discussion on the web visit >>>> https://groups.google.com/d/msgid/sympy/CAP7f1AirYPVS0vaN-kxmw%2BbqzHfwTA%2BRB0SmP7cU9BEQ-aPGgA%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/sympy/CAP7f1AirYPVS0vaN-kxmw%2BbqzHfwTA%2BRB0SmP7cU9BEQ-aPGgA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >>> 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 view this discussion on the web visit >>> https://groups.google.com/d/msgid/sympy/CANV73fFijGVbjwPaOx0OKh4fDtHYKqV01rj_TQp4tL3VVpc%3D%2Bw%40mail.gmail.com >>> <https://groups.google.com/d/msgid/sympy/CANV73fFijGVbjwPaOx0OKh4fDtHYKqV01rj_TQp4tL3VVpc%3D%2Bw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAJUjCNkE5y8EHxhG1XhfsFQax05SognCNM_5zPGR72JYaVffvg%40mail.gmail.com > <https://groups.google.com/d/msgid/sympy/CAJUjCNkE5y8EHxhG1XhfsFQax05SognCNM_5zPGR72JYaVffvg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "sympy" group. 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