Provided by: librheolef-dev_5.93-2_i386 bug


       2D -- rate of deformation tensor


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


       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,
                        / Omega


            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.


       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");