Solvers require as one argument a user function to work on which have to be provided by the
user. These callbacks typically are of the form
-
...
return result
Please note that this function must return the exact number of arguments
as given in the example. The wrappers around callbacks go a long way to try to provide
meaningfull error messages. If a solver fails, please check that the number of input and
output arguments it takes are correct
Release 0.9, documentation updated on October, 2008.