On Mon, Mar 31, 2008 at 02:42:14PM +0200, Kristen Kaasbjerg wrote: > Anders Logg wrote: > > On Mon, Mar 31, 2008 at 02:26:45PM +0200, Kristen Kaasbjerg wrote: > > > >> Hi, > >> > >> I would like to plot a function that is the difference between a > >> DiscreteFunction and a UserFunction. Can this be done in any smart ways ? > >> > >> The only way I can think of is to create a new user defined function > >> that contains the two Functions above, which does the subtraction in the > >> eval function, and then save this function to vtk format. > >> This, however, will call the eval method of the DiscreteFunction which > >> includes cell searching etc. Just sounds a bit cumbersome to me when the > >> mesh contains say 500.000 elements. > >> > >> Kristen > >> > > > > I would recommend to project the difference to an appropriate finite > > element space and then plot the projection. > > > > > Ok, are there any examples around that illustrate how to do this ? > > Kristen
v = TestFunction(...) u = TrialFunction(...) f = Function(...) g = Function(...) a = v*u*dx L = v*(f - g)*dx -- Anders _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
