## SYNOPSIS

form (const space V, const space& T, "2D");

## DESCRIPTION

Assembly the form associated to the rate of deformation tensor, i.e. the symmetric part of the gradient of a vector field. These derivative are usefull in fluid mechanic and elasticity.

/ | b(u,tau) = | 2 D(u) : tau dx, | / Omegawhere

2 D(u) = grad u + (grad u)^T

If the V space is a vector-valued **P1** (resp. **P2**)
finite element space, the T space may be
a tensor-valued **P0** (resp. **P1d**) one.

## EXAMPLE

The following piece of code build the Laplacian form associated to the P1 approximation:

geo omega ("square"); space V (omega, "P1", "vector"); space T (omega, "P0", "tensor"); form b (V, T, "2D");