id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
17701,"diff(f,t) should work even with Function objects",rws,,"{{{
sage: t = var('t')
sage: sage: f = function('f')(t)
sage: diff(f,x,x)
0
sage: desolve(diff(f,t) - (f+1)/(t+1), f)
(_C - 1/(t + 1))*(t + 1)
sage: sage: f = function('f')
sage: diff(f,t)
...
TypeError: unable to convert f to a symbolic expression
sage: diff(sin,t)
...
TypeError: unable to convert f to a symbolic expression
}}}
The same error can be had with the simple `SR(sin)`, i.e., any function object in contrast to the resp. function call, which returns an `Expression`.
Since function objects can be used in other context it seems they should be part of symbolic expressions too. This ticket however will limit itself to giving a better error message in `SR.coerce` and handling `Function` objects in `calculus/functional.py:derivative()`.
See also #15025",defect,needs_work,major,sage-7.2,calculus,,,,,Ralf Stephan,Travis Scrimshaw,N/A,,u/rws/diff_f_t__should_work_even_with_function_objects,0cecec3ff4c53e8e030311b4b55fc9e7d96a8cda,,