CFD Online Discussion Forums - [General] Programmable filter

Crosspost from https://discourse.paraview.org/t/pro...-lambda2/12188

I followed this guide in an attempt to get Eigenvalues / Lambda2 calculated by ParaView:
https://discourse.paraview.org/t/eig...mputation/9307

My script looks like this:

Code:

import numpy as np

from vtk.numpy_interface import algorithms as algs



input=inputs[0]

Velocity_Vector = input.PointData[‘velocity’]

STRAIN = strain(Velocity_Vector)

V_gradient = gradient(Velocity_Vector)

AAA=STRAIN**2+(V_gradient - STRAIN)**2

print(shape(AAA))

Lambda_2 = np.linalg.eigvals(AAA[:])

Lambda_2 = np.real(Lambda_2)

output.PointData.append(Lambda_2, ‘Lambda_2’)

Which seems to work up to the line “Lambda_2 = np.linalg.eigvals(AAA[:])”
Here I get the error “numpy.linalg.LinAlgError: 0-dimensional array given. Array must be at least two-dimensional”
The shape of AAA is printed as (12058557,3,3)
The input for this filter is point data with a velocity field in vector form.
PV version 5.11.0

I am new to programmable filters and Python in general. A nudge into the right direction would be greatly appreciated.