Question #109900 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/109900
Garth Wells proposed the following answer: On 06/05/10 14:22, Marie Rognes wrote: > Garth Wells wrote: >> Question #109900 on DOLFIN changed: >> https://answers.launchpad.net/dolfin/+question/109900 >> >> Garth Wells proposed the following answer: >> >> On 06/05/10 13:52, Marie Rognes wrote: >>> Achim Schroll wrote: >>>> New question #109900 on DOLFIN: >>>> https://answers.launchpad.net/dolfin/+question/109900 >>>> >>>> for a plain Poisson eqn with pure Neumann b.c., how to specify the >>>> scaling condition u*dx = 0 ? >>> >>> If you have a recent dolfin, you can introduce a constant c acting as a >>> Lagrange multiplier corresponding to the constraint. See example below. >>> >> >> Nice. What does 'R' stand for in the definition of the space Q? >> > > "Real" (Space of real numbers) > OK. It would good to add this example as a demo to DOLFIN. Garth > > -- > Marie > >> Garth >> >>> from dolfin import * >>> >>> mesh = UnitSquare(32, 32) >>> V = FunctionSpace(mesh, "CG", 1) >>> Q = FunctionSpace(mesh, "R", 0) >>> M = V * Q >>> >>> (u, c) = TrialFunctions(M) >>> (v, d) = TestFunctions(M) >>> >>> f = Expression("x[0]*x[1]*sin(pi*x[0])") >>> >>> a = dot(grad(v), grad(u))*dx + d*u*dx + c*v*dx >>> L = v*f*dx >>> >>> pde = VariationalProblem(a, L) >>> u_h = pde.solve() >>> >>> plot(u_h[0]) >>> interactive() >>> >>> >>> -- >>> Marie >>> >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~dolfin >>> Post to : [email protected] >>> Unsubscribe : https://launchpad.net/~dolfin >>> More help : https://help.launchpad.net/ListHelp >> > > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp -- You received this question notification because you are a member of DOLFIN Team, which is an answer contact for DOLFIN. _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
