There is also some concept of operators in the quantum module. I don't remembr if it does what you want or not.
You could try just making an object that overrides __rmul__. But if any operation manually creates a Mul with your object, it won't be called (this is a long running issue that we are still thinking about how to fix. See http://code.google.com/p/sympy/issues/detail?id=1941). Aaron Meurer On Sat, Jan 26, 2013 at 5:45 PM, ruoyu zhang <[email protected]> wrote: > I want to do some calculation like this: > > [cos(theta), -sin(theta)] [Ld*p + R, -Lq*omega] [cos(theta), > sin(theta)] [Id] > * * > * > [sin(theta), cos(theta)] [Ld*omega, Lq*p + R] [-sin(theta), > cos(theta)] [Iq] > > This is a part of motor equation expressed in matrix multiplication，Id, Iq, > theta are functions of t (time), p is the differential operator, so this > isn't a simple multiplication. I will do this kind of calculation a lot, so > I want to find a generic method. > > > > 在 2013年1月26日星期六UTC+9下午10时45分08秒，Stefan Krastanov写道： >> >> Before suggesting a solution I need to point out a problem with your >> suggestion. Namely, multiplication and application are two very >> different operation (there is overlap (e.g. matrix multiplication) but >> I will leave it out for the moment). SymPy does not have support for >> this type of "abuse of notation" for the moment. If you are >> interesting implementing it yourself your best shot (in my opinion) >> would be to get inspiration by the matrix expression module and the >> rewrite rules module. >> >> On the other hand if you want to use simple vanilla python for all >> this you can just use the `diff` global function but presumably you do >> not want that in order to facilitate automatic simplifications like >> "2*p - p -> p". >> >> If this is the case (and you are absolutely sure that this is >> necessary (usually it is not)) you can try to use the differential >> geometry module (in differential geometry vector fields are >> differential operators). If you know the formalism it will be very >> easy to use, however if you do not know it you will need to read >> something more than just the documentation. >> >> >> http://docs.sympy.org/dev/modules/diffgeom.html#sympy.diffgeom.BaseVectorField >> >> On 25 January 2013 23:49, ruoyu zhang <[email protected]> wrote: >> >>>> p = DifferentialOperator(t) >> >>>> a * p * f(t) >> > Derivative(f(t), t)*a >> > >> > p is a DifferentialOperator, when it multiply with some expression at >> > right >> > side, it calculates the derivative of the expression. >> > >> > -- >> > You received this message because you are subscribed to the Google >> > Groups >> > "sympy" group. >> > To post to this group, send email to [email protected]. >> > To unsubscribe from this group, send email to >> > [email protected]. >> > Visit this group at http://groups.google.com/group/sympy?hl=en. >> > For more options, visit https://groups.google.com/groups/opt_out. >> > >> > > > -- > 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?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
