CauchyGreenStrain

[softmattertheory]

Makes the Cauchy Green strain tensor:

C = (F G - 1)/2

where:

• F is the gram matrix in the deformed frame.
• G is the INVERSE of the gram matrix in the reference frame.

C vanishes if the deformed and reference frames coincide.

You must supply a reference mesh to your Integral constructor; you can then call cgtensor() within an integrand:

fn integrand(x, f) {
   var cg = cgtensor()
   return cg.trace()
}

var a = AreaIntegral(integrand, phi, reference=mref)