I don't understand how it works...
I tried to do a test:
class A(Basic):
def _eval_power(self, a):
return Integer(12345)
a = A()
print exp(a)
print E**a
this gives me exp(A()) and not 12345
On Tuesday, June 25, 2013 9:39:09 PM UTC+2, Aaron Meurer wrote:
>
> On Tue, Jun 25, 2013 at 2:32 PM, F. B. <[email protected] <javascript:>>
> wrote:
> > Can this be done on the DifferentialOperator too?
>
> Sure, _eval_power works on everything.
>
> >
> > It would be nice to have a simple implementation of the exponential of a
> > diff operator, such as exp(diff_op_instance), it would be very helpful
> for
> > many physicists.
> >
> > (by the way, the exp of a DifferentialOperator requires pdsolve to be
> able
> > to handle initial conditions... I think it's going to take some time)
>
> Not if you submit a pull request...
>
> Aaron Meurer
>
> >
> >
> > On Monday, June 24, 2013 11:06:24 PM UTC+2, Aaron Meurer wrote:
> >>
> >> Actually, fixing this just involves fixing
> >> https://code.google.com/p/sympy/issues/detail?id=1799, because Pow
> >> already has this logic (_eval_power).
> >>
> >> Oh, and I guess Matrix._eval_power would need to be implemented
> >> (currently it raises NotImplementedError, but this is easy to fix,
> >> just make a**Matrix give exp(log(a)*Matrix). Even with that fixed, you
> >> could do E**Matrix, before issue 1799 is fixed.
> >>
> >> Aaron Meurer
> >>
> >> On Mon, Jun 24, 2013 at 12:37 PM, F. B. <[email protected]> wrote:
> >> > Hi, I noticed the Matrix.exp() function which calculates the
> exponential
> >> > of
> >> > a Matrix.
> >> >
> >> > The exp() function fails when calling exp(matrix) because it does not
> >> > recognize the matrix object.
> >> >
> >> > exp is a class inheriting the "Function" object.
> >> >
> >> > What about creating an "ForwardFunction" object which tries to look
> for
> >> > methods having the same name of the class to apply it?
> >> >
> >> > For example, the exp() function would not recognize a Matrix object
> in
> >> > its
> >> > algorithm, but would notice the Matrix.exp() method on its arg and
> call
> >> > it.
> >> >
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