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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | # Copyright (C) 2005-2009 Anders Logg and Harish Narayanan
#
# This file is part of UFL.
#
# UFL is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# UFL is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with UFL. If not, see <http://www.gnu.org/licenses/>.
#
# The bilinear form a(v, u) and Linear form L(v) for the Stokes
# equations using a mixed formulation (Taylor-Hood elements) in
# combination with the lhs() and rhs() operators to extract the
# bilinear and linear forms from an expression F = 0.
cell = triangle
P2 = VectorElement("Lagrange", cell, 2)
P1 = FiniteElement("Lagrange", cell, 1)
TH = P2 * P1
(v, q) = TestFunctions(TH)
(u, p) = TrialFunctions(TH)
f = Coefficient(P2)
F = (inner(grad(v), grad(u)) - div(v)*p + q*div(u))*dx - dot(v, f)*dx
a = lhs(F)
L = rhs(F)
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