[ffbof]

I investigated that function is called in the updateInterfaceMatrix method of the cyclicFvPatchField. Going deeper,
the implementation of the call can be found in the cyclicLduInterfaceField::transformCoupleField

there the following code confuses me a bit

scalar forwardScale =
pow(diag(forwardT()[0]).component(cmpt), rank());

1. forwardT is a 3x3 tensor which defines a rotation ok
2. diag gives back the diagonal of the forwardT()[0]
3. but what is forwardT()[0] ?
4. pow is clear
5. why is that scale multiplied with a scalar
for (label facei=0; facei<sizeby2; facei++)
{
pnf[facei] *= forwardScale;
pnf[facei + sizeby2] *= reverseScale;
}
My explanation for that is that the forwardScale is a kind of jacobi
matrix because the pnf[facei] is a derivative or a sum of derivatives.

But i feel not good with that vague explanation.

So does anybody know what is going on in that part of OpenFOAM ??
And is there literature which explains what the forwardScale is?

Thank you for reading
Franz

[thang_cegroup]

I know its been a long time but do you figure out anything about this function ? If yes , could u explain it for me ? I need to understand this function to implement cyclic bc for block matrix in foam extend 4-0 since its not implemented for block matrix