Dear Jason, I just did what you suggested. I hope I did it right. I tried to attach the program I used, but I could not do it.
Peter On Tue 29. Jun 2021 at 15:17 Jason Moore <moorepa...@gmail.com> wrote: > Peter, > > Feel free to open an issue on the sympy github repository with precise > instructions on reproducing this and we can look into it. > > Jason > moorepants.info > +01 530-601-9791 > > > On Tue, Jun 29, 2021 at 2:45 PM Peter Stahlecker < > peter.stahlec...@gmail.com> wrote: > >> Dear Jason, >> >> Maybe it is not 'Body' vs. 'Axis', but my clumpsy programming! >> The results look reasonable, but maybe my kinematic equatios are clumsy >> or....? >> >> Take care! >> >> Peter >> >> On Tue 29. Jun 2021 at 15:24, Jason Moore <moorepa...@gmail.com> wrote: >> >>> Peter, >>> >>> Sounds like that could use some improvements. I'm not sure why the body >>> fixed rotations are so much worse. >>> >>> Jason >>> moorepants.info >>> +01 530-601-9791 >>> >>> >>> On Tue, Jun 29, 2021 at 1:00 PM Peter Stahlecker < >>> peter.stahlec...@gmail.com> wrote: >>> >>>> Dear Jason, >>>> >>>> Thanks! >>>> I tested it right away, and I counted the operations of an entry of rhs >>>> = KM.rhs() >>>> >>>> For ‚Body‘ I got the count 245,633 >>>> With the auxiliary frames the count was 13,235 >>>> >>>> Thanks again and stay healthy! >>>> >>>> I will keep on testing this. >>>> >>>> Peter >>>> >>>> >>>> >>>> >>>> On Tue 29. Jun 2021 at 12:32 Jason Moore <moorepa...@gmail.com> wrote: >>>> >>>>> Peter, >>>>> >>>>> THey are equivalent other than one may provide a simpler set of >>>>> direction cosine matrices and angular velocity definitions. The "Body" >>>>> method should give simpler equations of motion in the end because we try >>>>> to >>>>> use pre-simplified forms of the equations. I don't know why you'd see >>>>> faster with the intermediate frame method. >>>>> >>>>> You can use sympy's count_ops() function to see how many operations >>>>> each symbolic form gives. The one with more operations should ultimately >>>>> be >>>>> slower when lambdified(). >>>>> >>>>> Jason >>>>> moorepants.info >>>>> +01 530-601-9791 >>>>> >>>>> >>>>> On Tue, Jun 29, 2021 at 5:09 AM Peter Stahlecker < >>>>> peter.stahlec...@gmail.com> wrote: >>>>> >>>>>> When I want to do this, it seems to me there are these possibilities: >>>>>> >>>>>> 1. >>>>>> A = N.orientnew(‚A‘, ‚Body‘, [q1, q2, q3], ‚123‘) >>>>>> This does it in one step >>>>>> >>>>>> 2. >>>>>> I use two intermediate frames and use the word ‚Axis‘ instead of >>>>>> ‚Body‘ >>>>>> >>>>>> Geometrically, this should be the same, but it seems to me, that with >>>>>> the intermediate frames establishing Kane‘s equations, lambdifying them >>>>>> and >>>>>> doing the numerical integration is MUCH faster. >>>>>> >>>>>> Are methods 1 and 2 not equivalent, as I assumed, or am I doing >>>>>> something wrong? >>>>>> >>>>>> Thanks for any explanation! >>>>>> >>>>>> -- >>>>>> 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/d1597154-f8a8-42fa-b29b-6e8f57062441n%40googlegroups.com >>>>>> <https://groups.google.com/d/msgid/sympy/d1597154-f8a8-42fa-b29b-6e8f57062441n%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/CAP7f1AhvTHkfn8_Wc7L9i7em3QvDHn6MPBHoWwqvK9qOUw3QfA%40mail.gmail.com >>>>> <https://groups.google.com/d/msgid/sympy/CAP7f1AhvTHkfn8_Wc7L9i7em3QvDHn6MPBHoWwqvK9qOUw3QfA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- >>>> Best regards, >>>> >>>> Peter Stahlecker >>>> >>>> -- >>>> 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/CABKqA0bdrLLiCY7w3yG_3sPTmx7O4Z00tn-mLSssj0rvT4m9QA%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/sympy/CABKqA0bdrLLiCY7w3yG_3sPTmx7O4Z00tn-mLSssj0rvT4m9QA%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/CAP7f1Agxr30mQjCXBF31uH1qxr6OTJx2dL%2B6SkzNAyfNnytQEQ%40mail.gmail.com >>> <https://groups.google.com/d/msgid/sympy/CAP7f1Agxr30mQjCXBF31uH1qxr6OTJx2dL%2B6SkzNAyfNnytQEQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> Best regards, >> >> Peter Stahlecker >> >> -- >> 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/CABKqA0afGED8G8qNvLg-eYNC%2B1NEt%2BBqGZUob5N3Bc%3DWgonP6Q%40mail.gmail.com >> <https://groups.google.com/d/msgid/sympy/CABKqA0afGED8G8qNvLg-eYNC%2B1NEt%2BBqGZUob5N3Bc%3DWgonP6Q%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/CAP7f1Ajb_Xr0m2gRcEPHFRnPYALg2_thtS7swTXqAzncY0bYdQ%40mail.gmail.com > <https://groups.google.com/d/msgid/sympy/CAP7f1Ajb_Xr0m2gRcEPHFRnPYALg2_thtS7swTXqAzncY0bYdQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- Best regards, Peter Stahlecker -- You received this message because you are subscribed to the Google Groups "sympy" group. 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