mixed_poisson.py
96afb4176b70master

mixed_poisson.py
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			from matplotlib import pyplot as plt
			plt.jet()
			import fenics as fen

			# Create mesh and define function space
			mesh = fen.UnitSquareMesh(10, 10)
			CG1 = fen.FiniteElement("P", fen.triangle, 1)
			R0 = fen.FiniteElement("R", fen.triangle, 0)
			element = fen.MixedElement([CG1, R0])
			W = fen.FunctionSpace(mesh, element)

			# Define variational problem
			(u, c) = fen.TrialFunction(W)
			(v, d) = fen.TestFunctions(W)
			f = fen.Expression("10*exp(-(pow(x[0] - 0.5, 2) + pow(x[1] - 0.5, 2)) / 0.02)",
			element = CG1)
			g = fen.Expression("-sin(5*x[0])", element = CG1)
			a = (fen.inner(fen.grad(u), fen.grad(v)) + cv + ud)*fen.dx
			L = fvfen.dx + gvfen.ds

			# Compute solution
			w = fen.Function(W)
			fen.solve(a == L, w)
			(u, c) = w.split()

			# Plot solution
			plt.figure()
			p = fen.plot(u)
			plt.colorbar(p)
			plt.show(), plt.close()