Ask Your Question
2

Assumptions on symbolic functions

asked 2018-03-16 07:39:00 -0500

Marco Caliari gravatar image

updated 2018-03-16 09:35:50 -0500

I have a symbolic function f = function('f')(x). Is there a way to assume it is real and get abs(exp(I*f)) = 1?

edit retag flag offensive close merge delete

1 answer

Sort by ยป oldest newest most voted
1

answered 2018-03-17 04:05:09 -0500

Emmanuel Charpentier gravatar image

updated 2018-03-17 04:06:52 -0500

None at the moment, as far as I know.

Note however that :

  • maxima has such a facility (see maxima.declare?) ;
  • similarly, Sympy has such a facility (it even has two, the newer progressively replacing the older) ;
  • there are some reported bugs pointing the the way sage handles assumptions and tests thereof, and these bugs are worked on.

You might try to isolate the part of your computations where you need such a handling, do them in maxima or Sympy, and reimport the relevant results.

Note also that you can

assume(f(x)>0)

But that won't do a thing about bool(f(2*x+1)>0)...

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

Stats

Asked: 2018-03-16 07:39:00 -0500

Seen: 36 times

Last updated: Mar 17