#18092: evaluating symbolic expressions (without conversion to SR, i.e.,
staying in
ring of values)
-------------------------+-------------------------------------------------
Reporter: | Owner:
dkrenn | Status: needs_info
Type: | Milestone: sage-6.6
enhancement | Resolution:
Priority: major | Merged in:
Component: | Reviewers:
symbolics | Work issues:
Keywords: sd66 | Commit:
Authors: | 276f0f3d3583c66c7e137350c578e8588c9b236d
Daniel Krenn | Stopgaps:
Report Upstream: N/A |
Branch: |
u/dkrenn/SR/eval |
Dependencies: |
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Comment (by nbruin):
Replying to [comment:18 dkrenn]:
> What if
> {{{
> f = SR(1+2^x)
> }}}
> or something worse (including e.g. exp, log, sin, ... or other
functions)? There are no parents (except SR) for any of these constructs.
And indeed it's tricky to evaluate the result. What is `2^<power series>`?
I guess `exp(log(2)*x)`, which requires a ring that contains both `log(2)`
and inverses of all integers., so that doesn't work in `Z[[t]]`. I think
Sage is right in putting the onus on the user to first find a parent in
which the expression fits and where the evaluation behaviour is the
desired one.
Anyway, `fast_callable` takes a best effort approach towards compiling a
program that tries to perform the evaluation, so that might be your best
bet.
--
Ticket URL: <http://trac.sagemath.org/ticket/18092#comment:19>
Sage <http://www.sagemath.org>
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