On Thu, May 22, 2008 at 11:34:54AM +0200, Evan Lezar wrote: > On Thu, May 22, 2008 at 12:42 AM, Anders Logg <[EMAIL PROTECTED]> 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) :-) -- Anders _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
