Hello everyone,

I want to ask about a pro=
blem in the computation of error and in the exportation of solution to &quo=
t;.vtk" file:

I have programmed a non-conforming element in two dimension which con=
tains 6 degrees of freedom (4 in the vertices of rectangle + 2 second =C2=
=A0 derivative with respect to each variable calculated in the center of re=
ctangle).=C2=A0 I apply this element to the planar elastic problem without =
pression.=C2=A0In the model "elastostatic.cc" of directory tests =
we find=C2=A0

=C2=A0** if (data_f=
em_name.size() =3D=3D 0) {**

=

So at the =
beginning I set the "**DATA_FEM_TYPE =3DFEM_QK(2,1)"**** **a=
nd FEM_TYPE =3D "my element" because my element is n=
ot of=C2=A0Lagrange=C2=A0type. I got an approximate solution whi=
ch is not accurate when we look to the file "sol.vtk", but for th=
e error I get an error with precision "e-7" and "e-6"=
=C2=A0for the L2 norm and H1 norm, respectively. The rate=C2=A0of convergence in this case for the bo=
th norms is "**=3D2**".

However when I use the same fini=
te element=C2=A0**"my element" =C2=A0**for =C2=
=A0DATA_FEM_TYPE, FEM_TYPE and to apply the boundary conditions (just Diric=
hlet conditions in my case). I get an approximate solution more precise whe=
n I look to "Sol.vtk". The pourcentage of error is "Max valu=
e of error/max value of Exact solution =3D 5%" but in this case the er=
ror is too large and its precision is "e-2" for the norm L2 and &=
quot;e-0" for the norm H1, but if I compute the order of convergence b=
y these values of error, I got the optimal orde for H1 norm "**=3D1" but I can't get it for the L2 norm "=3D0.33".****=
**