features.py

computeFeatures_torch(I1, I2, I3):

Transforms the three principal invariants of the Cauchy-Green deformation tensor into mixed-deviatoric-volumetric invariants and returns them in a concatenated array.

• \(J = \det(\mathbf{F}) = I_3^{1/2}\)
• \(\tilde {I_1} = J^{-2/3}I_1\)
• \(\tilde {I_2} = J^{-4/3}I_2\)

Input Arguments

• I1 - 1st invariant

• I2 - 2nd invariant

• I3 - 3rd invariant

Output Arguments

• x - \([\tilde {I_1}, \tilde {I_2}, J]\)

getNumberOfFeatures():

Compute number of features.

Input Arguments

• none

Output Arguments

• features.shape[1] - number of features

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