/usr/lib/python2.7/dist-packages/FIAT/lagrange.py is in python-fiat 1.6.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 | # Copyright (C) 2008 Robert C. Kirby (Texas Tech University)
#
# This file is part of FIAT.
#
# FIAT 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.
#
# FIAT 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 FIAT. If not, see <http://www.gnu.org/licenses/>.
from . import finite_element, polynomial_set, dual_set, functional
class LagrangeDualSet( dual_set.DualSet ):
"""The dual basis for Lagrange elements. This class works for
simplices of any dimension. Nodes are point evaluation at
equispaced points."""
def __init__( self, ref_el, degree ):
entity_ids = {}
nodes = []
# make nodes by getting points
# need to do this dimension-by-dimension, facet-by-facet
top = ref_el.get_topology()
cur = 0
for dim in sorted( top ):
entity_ids[dim] = {}
for entity in sorted( top[dim] ):
pts_cur = ref_el.make_points( dim, entity, degree )
nodes_cur = [ functional.PointEvaluation( ref_el, x ) \
for x in pts_cur ]
nnodes_cur = len( nodes_cur )
nodes += nodes_cur
entity_ids[dim][entity] = list(range(cur, cur+nnodes_cur))
cur += nnodes_cur
dual_set.DualSet.__init__( self, nodes, ref_el, entity_ids )
class Lagrange( finite_element.FiniteElement ):
"""The Lagrange finite element. It is what it is."""
def __init__( self, ref_el, degree ):
poly_set = polynomial_set.ONPolynomialSet( ref_el, degree )
dual = LagrangeDualSet( ref_el, degree )
finite_element.FiniteElement.__init__( self, poly_set, dual, degree )
if __name__=="__main__":
from . import reference_element
# UFC triangle and points
T = reference_element.UFCTriangle()
pts = T.make_lattice(1)
# pts = [(0.0, 0.0), (1.0, 0.0), (0.0, 1.0)]
# FIAT triangle and points
# T = reference_element.DefaultTriangle()
# pts = [(-1.0, -1.0), (1.0, -1.0), (-1.0, 1.0)]
L = Lagrange(T, 1)
Ufs = L.get_nodal_basis()
print(pts)
for foo, bar in list(Ufs.tabulate( pts, 1 ).items()):
print(foo)
print(bar)
print()
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