[GiNaC-list] Differentiation of a function with respect to a tensor

[Bernardo Rocha]

Hi everyone,

I've recently discovered GiNaC and I'm really excited about its
capabilities. There is one thing that I would like to know if it is able to
do that I haven't found in the tutorial.pdf or in any other place that I've
searched.

I would like to know if, given a function \Psi=\Psi(E), like the strain
energy function for the St. Venant-Kirchhoff material

\Psi(E) = 0.5 * \lambda * (tr E)^2 + \mu E:E

is it possible to differentiate it with respect to E, that is i would like
to compute \frac{\partial \Psi}{\partial E}. If this is possible, could
someone please send some examples or maybe point to which classes should I
use to do that?

That's all for now. Many thanks in advance.

Best regards,
Bernardo M. R.
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