id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
17445,Missing documentation of derivative operator/notation,schymans,,"Taking the derivative of a symbolic function returns the D-notation:
sage: var('x y z')
sage: f(x) = function('f',x,y,z);
sage: f(x).diff(x,y)
D[0, 1](f)(x, y, z)
Unfortunately, the meaning of this notation is not documented anywhere, neither in diff(), nor in derivative() nor in function(). There is a ton of tickets about improving ambiguities and malfunctions related to this notation, but it would be very helpful to at least document how it is supposed to work and what it means if a user sees output as above.
See here for related tickets:
* #6344 - allow typesetting in ""diff"" format (possibly only as non-default option)
* #6756 - add ''input'' to Sage in ""diff"" format for derivatives (the most controversial)
* #6480 - clarify or fix substituting functions inside of symbolic derivatives
* #7401 - bug in our interaction with Maxima with evaluating derivative at a point (needs work due to multivariate derivatives not being there)
* #12796 - allow evaluation at points
and this discussion:
https://groups.google.com/forum/#!topic/sage-devel/_xD5lymnTuo
",enhancement,new,major,sage-6.5,symbolics,,,kcrisman eviatarbach,,schymans,,N/A,,,,,