id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
21758,Hold symbolic powers unevaluated if evaluation fails,rws,,"Automatic evaluation of symbolic expressions of ""numerics"" prevents construction of such expressions despite them being perfectly numerically approximatable (or otherwise useful) if exact evaluation in the algebraic sense fails. This is usually not a problem with function expressions (because of the easily added `hold=True`), and sums and products (?), but powers have to be constructed awkwardly:
{{{
sage: SR(2) ^ SR(QQbar(sqrt(2)))
Traceback (most recent call last):
...
TypeError: no canonical coercion ...
sage: SR(2).power(SR(QQbar(sqrt(2))), hold=True)
2^1.414213562373095?
}}}
The ticket catches `TypeError`s in the first case and automatically uses the second form, to allow:
{{{
sage: SR(2) ^ SR(QQbar(sqrt(2)))
2^1.414213562373095?
}}}
",enhancement,needs_work,major,sage-7.5,symbolics,,,vdelecroix,,Ralf Stephan,,N/A,,u/rws/hold_symbolic_powers_unevaluated_if_evaluation_fails,49ab13301f5b44f946701f3fdcaff6c4613c0de7,,