I meant xreplace(). Jason moorepants.info +01 530-601-9791
On Mon, Oct 28, 2019 at 8:57 AM Ashith Shyam <[email protected]> wrote: > Thank You Jason. Really appreciate it. > > Ash > > On Mon, Oct 28, 2019 at 3:07 PM Jason Moore <[email protected]> wrote: > >> If you have an expression you can use `.replace({q1: q1_sym})`. >> >> The code generation tools in PyDy can be directly used to code gen >> matrices with dynamicsymbols: >> https://pydy.readthedocs.io/en/stable/codegen/codegen.html >> >> Jason >> moorepants.info >> +01 530-601-9791 >> >> >> On Mon, Oct 28, 2019 at 6:00 AM Ashith Shyam <[email protected]> wrote: >> >>> Thanks Jason for the reply. As I have mentioned before, my actual system >>> is a bit more complex with the manipulator attached to a floating base. >>> There are several non-holonomic constraints as well. I am not sure if these >>> could be addressed by pydy or may be it will but still I need to go through >>> examples and learn and develop again. >>> Could you please let me know how to replace the functions of time with >>> ordinary symbols. I am expecting something like q1(t) to be q[0] and d >>> q1(t) /dt to be dq[0]? >>> >>> Ash >>> >>> On Mon, Oct 28, 2019 at 12:39 PM Jason Moore <[email protected]> >>> wrote: >>> >>>> https://github.com/pydy/pydy will do all this for you with just a few >>>> commands. >>>> >>>> If you want to use the code generation tools in sympy directly, it may >>>> help to replace the functions of time with ordinary symbols. >>>> >>>> Jason >>>> moorepants.info >>>> +01 530-601-9791 >>>> >>>> >>>> On Mon, Oct 28, 2019 at 4:04 AM Ash <[email protected]> wrote: >>>> >>>>> Hello >>>>> I am trying to develop equations of motion using sympy of a complex >>>>> system. It takes 4-5 minutes to get the mass matrix (M) and coriolis >>>>> vector >>>>> (C). Hence I decided to use sympy's codegen and try to make it fast. >>>>> I can write my equations as >>>>> >>>>> d^2 *q*/ dt^2 = M_inverse (Tau - C - G) >>>>> but M, C, Tau (torque) and G(gravity) are defined with respect to >>>>> state variables and its derivatives. And I cant figure out how to do it. >>>>> >>>>> I am attaching a simple two degree of freedom planar robot's code for >>>>> easy understanding of my problem. My state variables are the angles q1(t) >>>>> and q2(t) (dynamic symbols). There are other variables like lengths, mass, >>>>> inertia of the links which are defined as symbols. M(q(t)), C(q(t), >>>>> dq(t)), >>>>> G(q(t)) matrices are derived symbolically (line 14). My doubt is if I want >>>>> to play around with the numerical values of the variables in M, C, and G, >>>>> how can I efficiently generate code and cythonize and build wrapper? >>>>> >>>>> Any help would be really appreciated >>>>> >>>>> Thanks >>>>> >>>>> -- >>>>> 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 view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/sympy/eb589af0-2dca-4b8d-bfff-290a4767e20a%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/sympy/eb589af0-2dca-4b8d-bfff-290a4767e20a%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 [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/sympy/CAP7f1AjbK%2BKTZJV9z8XO3Y7x_S0%2B7xR969%2BK8GcptG-tgwue%2BQ%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/sympy/CAP7f1AjbK%2BKTZJV9z8XO3Y7x_S0%2B7xR969%2BK8GcptG-tgwue%2BQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >>> >>> -- >>> R.B. Ashith Shyam <https://sites.google.com/site/rbashithshyam/> >>> +44 7459909812 >>> >>> -- >>> 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 view this discussion on the web visit >>> https://groups.google.com/d/msgid/sympy/CAGassLARFMmfZ5uWfiN0y8KLWxfR19A2WtjJ%2Bjf-6OCyzfzDAQ%40mail.gmail.com >>> <https://groups.google.com/d/msgid/sympy/CAGassLARFMmfZ5uWfiN0y8KLWxfR19A2WtjJ%2Bjf-6OCyzfzDAQ%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 [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/CAP7f1AjOZocz%2B_xNgKCMy8Txp2%2BE69T7heLOPYbBubt6yTuNLg%40mail.gmail.com >> <https://groups.google.com/d/msgid/sympy/CAP7f1AjOZocz%2B_xNgKCMy8Txp2%2BE69T7heLOPYbBubt6yTuNLg%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > R.B. Ashith Shyam <https://sites.google.com/site/rbashithshyam/> > +44 7459909812 > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAGassLCvjZ8i3g0D1EYBvDUgZdmQP3LOFZ8NsjARwPh--EPymQ%40mail.gmail.com > <https://groups.google.com/d/msgid/sympy/CAGassLCvjZ8i3g0D1EYBvDUgZdmQP3LOFZ8NsjARwPh--EPymQ%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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAP7f1AjWmvHHgkqfSteSZkYg5Bh8DA0S0e7U%2BKWtXgr3BuyPRg%40mail.gmail.com.
