How to add a custom array to a polydata in paraview?

Question

I know that I can use the Calculator filter for operations on arrays, but I want to perform some more complicated computations. I managed to do it in Paraview python shell,

Answer 1

Better approach would be use the Programmable Filter to add the array to your input dataset. In ParaView 4.1, the following script can be added to the Script on Properties panel for the Programmager Filter

polydata = output
array = vtk.vtkIntArray()
array.SetNumberOfComponents(0)
array.SetName("regionsize")
for i in range(polydata .GetNumberOfPoints()):
    array.InsertNextValue(somecomputedvalue)
polydata.GetPointData().AddArray(array);