dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Thu, May 22, 2008 at 11:48:54AM +0200, Evan Lezar wrote:
> Thanks ... I am downloading paraview as we speak.
> 
> When I say plot the mesh - I mean plot the mesh and the function in
> the same viper window?

Try pressing 'w'.

-- 
Anders


> :)
> 
> On Thu, May 22, 2008 at 11:43 AM, Anders Logg <logg@xxxxxxxxx> wrote:
> > On Thu, May 22, 2008 at 11:34:54AM +0200, Evan Lezar wrote:
> >> On Thu, May 22, 2008 at 12:42 AM, Anders Logg <logg@xxxxxxxxx> wrote:
> >> > On Tue, May 20, 2008 at 09:43:54PM +0200, Evan Lezar wrote:
> >> >> Hi there
> >> >>
> >> >> As an initial attempt, I am trying to use fenics to compute the resonant
> >> >> modes of a rectangular waveguide - and as such I need to solve an
> >> >> eigenvalue problem of the form  [A]x = lambda[B]x where x represents a
> >> >> vector of coefficients of the basis functions used to calculate the
> >> >> entries of the stiffness ([A]) and mass ([B]) matrices.
> >> >>
> >> >> It is easy to assemble the matrices, and I have solved the eigenvalue
> >> >> problem using eigs() ... but now I have the calculated coefficients and
> >> >> I would like to plot the weighted sum of the basis functions (the finite
> >> >> element solution).
> >> >>
> >> >> Any help on the matter would be much appreciated.
> >> >>
> >> >> Thanks
> >> >> Evan
> >> >
> >> > Are you doing this in Python or C++?
> >> >
> >> > If x is the vector, then you can do
> >> >
> >> >  Function u(mesh, x, a);
> >> >
> >> > where a is the form in C++.
> >> >
> >> > In Python, you need to do
> >> >
> >> >  Function u(element, mesh, x);
> >> >
> >> > where element is the FiniteElement you have used for the trial space.
> >> >
> >> > To plot the solution, just do
> >> >
> >> >  plot(u);
> >> >
> >> >
> >>
> >> Thanks for the reply - something is happening now at least :)
> >>
> >> Now that I have the function - how do I specify at which coordinates
> >> it should be plotted?  At the moment, there are a couple of vectors
> >> being plotted, but I would like a higher density.
> >
> > The builtin plotting (Viper) has very limited functionality (by
> > intention). For more options, save to .pvd format and open in Paraview.
> >
> >> Also, is there a way to plot the mesh as well as the function in viper?
> >
> > Yes:
> >
> >  plot(mesh)
> >
> > :-)
> >
> >
> 
> 
>