The inline expression in the parameter file that we used previously is
too short and limited.  In particular, we want to be able to use the
same expression for error measurements.  However, for that we need
a function with a derivative.

[[Imported from SVN: r10063]]

Kudos to Carsten Gräser for those new Python functions.

[[Imported from SVN: r10028]]

[[Imported from SVN: r10026]]

I don't think I will need that again in the foreseeable future.
If ever it should be needed again the code can be taken from the
subversion archive.

[[Imported from SVN: r10020]]

The plan is to minimize the harmonic energy starting from the inverse
stereographic projection.  That projection already is the minimizer
of the energy, so it should be possible to measure convergence orders
against a known solution.

[[Imported from SVN: r10019]]

[[Imported from SVN: r10017]]

[[Imported from SVN: r10014]]

[[Imported from SVN: r10013]]

According to Christof Melcher, this produces a field of topological
charge q=1  (or -1, not sure).

[[Imported from SVN: r10006]]

[[Imported from SVN: r10001]]

[[Imported from SVN: r9999]]

[[Imported from SVN: r9618]]

[[Imported from SVN: r9617]]

[[Imported from SVN: r5726]]