Hi,
The reference docu are thy Python doc-strings. For every object you can use help like
Code:
help (mesh)
help (GridFunction)
Finding the maximum of an arbitrary function you can construct within NGSolve accurately and efficient ist not trivial. Calculating the max in all integration points or so would be easy, I am thinking about this possibility.
Now you can do this workaround:
Interpolate into an H1(order=1) gridfunction, and take the maximal value of the coefficient vector.
Best, Joachim