# Find maximum value of Gridfunction

Hello,

i have some trouble to find the maximum value of a GridFunction. I assume it must be very simple, but I can’t figure out how it works. Here is my code:

``````               # - - - - -

gfB = curl(gfA)

A_max = max(Norm(gfA))*1e-3     #Conversion from mm to m
B_max = max(Norm(gfB))*1e-6     #Conversion from mm^2 to m^2

print('-------------------------------')
print('max(|A|)       ', A_max, ' Vs/m')
print('max(|B|)       ', B_max, ' Vs/m^2')
print('-------------------------------')

# - - - - -``````

Is there any official description of the API? I always struggle to find out what methods are available and how they work.

Hi,

The reference docu are thy Python doc-strings. For every object you can use help like

``````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