ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 28 Nov 2018 19:41:43 +0100How to use the divergence of a finite function as the source term of another problemhttps://ask.sagemath.org/question/44492/how-to-use-the-divergence-of-a-finite-function-as-the-source-term-of-another-problem/ I use RT element to solve problem A and denote the finite element solution by sigma, sigma is a matrix-valued finite element function. I need to use the divergence of sigma to be the source term of another problem, the trial function space is vector-valued functions. But it doesn't work. The code is
from __future__ import print_function
from fenics import *
import matplotlib.pyplot as plt
mesh = UnitSquareMesh(8,8)
RT = VectorElement("RT",mesh.ufl_cell(), 1,2)
Q = FunctionSpace(mesh, RT)
V = VectorFunctionSpace(mesh, 'CG',1)
f = Expression((('x[0]*x[1]','x[0]'),('x[0]','x[0]*x[1]')),degree=2)
sigma = TrialFunction(Q)
tau = TestFunction(Q)
a = inner(sigma, tau)*dx
L = inner(f,tau)*dx
sigma = Function(Q)
solve(a == L, sigma)
def boundary(x, on_boundary):
return on_boundary
bc = DirichletBC(V, Constant((0.0, 0.0)), boundary)
u = TrialFunction(V)
v = TestFunction(V)
au = inner(grad(u), grad(v))*dx
Lu = inner(sigma,grad(v))*dx
u = Function(V)
solve(au == Lu, u, bc)adaWed, 28 Nov 2018 19:41:43 +0100https://ask.sagemath.org/question/44492/FEniCS on sagemathhttps://ask.sagemath.org/question/32895/fenics-on-sagemath/ Dr. Stein explains in the link below that FEniCS can be accessed on sagemath cloud. I followed the instructions in his post but i get an error that says: "No module named dolfin".
http://ask.sagemath.org/question/11002/can-fenics-be-setup-on-sagemath-cloud/?answer=16018#post-id-16018
I'd appreciate any help figuring out how to import dolfin in sagemath.
Thanks,sophiaSun, 27 Mar 2016 20:57:42 +0200https://ask.sagemath.org/question/32895/Can FEniCS be setup on Sagemath Cloud?https://ask.sagemath.org/question/11002/can-fenics-be-setup-on-sagemath-cloud/Is it possible to have the FEniCS packages setup on Sagemath Cloud? http://fenicsproject.org/about/
Has anyone had success with attempting this on Sagemath? I had tried initially through a terminal instance with no success.
Regards,
BrunoBruno_BateThu, 06 Feb 2014 14:15:14 +0100https://ask.sagemath.org/question/11002/