dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

Just replace "L2" by "M" and it should work.

"M" is a reserved keyword for functionals, just like "a" and "L" for
bilinear and linear forms.

-- 
Anders


On Mon, Jun 15, 2009 at 03:00:10AM -0500, Jehanzeb Hameed wrote:
> 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.
> >
> >
> >
> >> 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
> >> >
> >> >
> >> > -----BEGIN PGP SIGNATURE-----
> >> > Version: GnuPG v1.4.9 (GNU/Linux)
> >> >
> >> > iEYEARECAAYFAkovWqUACgkQTuwUCDsYZdGb3gCfa2gWnzealWzkjPoRj8hf3cr/
> >> > 0EUAoJh4mpaIzRU9eCnnC+XWlupu6SV0
> >> > =so4c
> >> > -----END PGP SIGNATURE-----
> >> >
> >> > _______________________________________________
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> >> >
> >> >
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> >
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v1.4.9 (GNU/Linux)
> >
> > iEYEARECAAYFAkov28sACgkQTuwUCDsYZdE8KQCdEI7wS27QaNw9knI2U9L+RVST
> > xeUAnRdLrrhAVzsBn6nO1b6CLEpF64ey
> > =a7iu
> > -----END PGP SIGNATURE-----
> >
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