I cant figure out how to generate a form file for norm, in C++. The
problem is that the form is quadratic in its arguments, and so isn't a
valid form according to ffc user manual. I tried it anyway, making a
file like this (just for testing):.
vecElement = VectorElement("Lagrange", "triangle", 1,3)
u = Function(vecElement)
L2 = dot(u,u)*dx
ffc doesnt make .h file, and exits with the following message:
"No forms or elements specified, nothing to do."
I tried compiling by "ffc -r quadrature l2norm.form", and again got
the same message.
Can someome please help amd point out what I can do?
Thanks,
-Jehanzeb
On Wed, Jun 10, 2009 at 11:14 AM, Anders Logg<logg@xxxxxxxxx> wrote:
On Wed, Jun 10, 2009 at 09:58:20AM -0500, Jehanzeb Hameed wrote:
Thanks. So I guess that means no such facility is available in C/C++ ?
No, since the computation depends on the space the functions are in
and so the code needs to be generated. In C++, you need to define a
form file for the norm. Look at
site-packages/dolfin/norm.py
for how to define the norms.
--
Anders
On Wed, Jun 10, 2009 at 2:03 AM, Anders Logg<logg@xxxxxxxxx> wrote:
On Tue, Jun 09, 2009 at 05:11:48PM -0500, Jehanzeb Hameed wrote:
Hello,
Is there a builtin function in dolfin to compute L^2 or H_1 norms? If
so, can you please point it out. If not, are there support functions
(e.g. a Gauss Quadrature table, computation of Jacobians, etc) which
can help in this?
Yes, this is available in the DOLFIN Python interface:
norm(v)
The default computes the L^2 norm. Several options are available:
L^2: norm(v, 'L2')
H^1: norm(v, 'H1') includes L^2 term
H^1_0: norm(v, 'H10') does not include L^2 term
H(div): norm(v, 'Hdiv') includes L^2 term
H(div): norm(v, 'Hdiv0') does not include L^2 term
H(curl): norm(v, 'Hcurl') includes L^2 term
H(curl): norm(v, 'Hcurl0') does not include L^2 term
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