Question #159694 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/159694
Johan Hake posted a new comment: What version of DOLFIN do you use. Just run dolfin-version from the command prompt. The itnerface of VariationalProblem has changed recently and it seams as you might have an older version. Johan On Monday May 30 2011 21:05:47 Praveen C wrote: > New question #159694 on DOLFIN: > https://answers.launchpad.net/dolfin/+question/159694 > > Hello > This is my first attempt at dolfin. I am solving a 1-d convection-diffusion > equation > > (u^2/2)_x - u_xx = f > u(0) = u(1) = 0 > > So I do the following > > > # Create mesh and function space > mesh = UnitInterval(50) > V = FunctionSpace(mesh, "CG", 1) > > # Sub domain for Dirichlet boundary condition > def DirichletBoundary(x): > return x[0] < DOLFIN_EPS or x[0] > 1.0 - DOLFIN_EPS > > # Define variational problem > u = Function(V) > f = Expression("10.0*x[0]*(1.0-x[0])*sin(x[0])") > > du = TrialFunction(V) > v = TestFunction(V) > > F = (-0.5*u**2*grad(v) + dot(grad(u), grad(v)))*dx - f*v*dx > dF= derivative(F, u, du) > > # Define boundary condition > u0 = Constant(0.0) > bc = DirichletBC(V, u0, DirichletBoundary) > > problem = VariationalProblem(F, dF, bc) > u = problem.solve() > > But this gives me following error > > RuntimeError: *** Error: Unable to extract trial space for solution of > variational problem, is 'a' bilinear? > > Can you help me with this please ? > > Thanks > praveen -- 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 : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
