d_dx(7)
NAME
d_dxi -- derivatives
SYNOPSIS
form (const space V, const space& M, "d_dx0"); form (const space V, const space& M, "d_dx1"); form (const space V, const space& M, "d_dx2");
DESCRIPTION
@tex Assembly the form associated to a derivative operator from the $V$
finite element space to the $M$ one: $$ b_i(u,q) = int_ega { {artial
u} x}, iin 0,1,2 $$ for all $u in V$ and $q in M$. In the axisymetric
{t rz} case, the form is defined by $$ b_0(u,q) = int_ega { {artial
u} }, iin 0,1,2 $$ Note that, by integration by part $$ b_0(u,q) = int_ega u t( {1 r{} iin 0,1,2 $$ This expression appears in the divergence operator. @end tex
If the V space is a `P1' (resp. `P2') finite element space, the M space
may be a `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");
space M (omega, "P0");
form b (V, M, "d_dx0");
LIMITATIONS
- Only edge, triangular and tetrahedal finite element meshes are yet supported.