Interpolation in mixed formulation

1

I am using fenics Ubuntu, please i am trying to interpolate the final solution onto a finer mesh in a mixed formulation. Here is my code for the final solution in which i want to interpolate but seems to not get it right.

u = Function(ME_coarse) # current solution
c, mu = u.split()

Step in time

t = 0.0

for j in range(N):

  t += dt


# RHS weak form of Convex splitting

  L =  (c0*q  + 3*((c0)**2)*v - 2*((c0)**3)*v)*dx

  solve(a == L, u)
  u.t = t
  u0.assign(u)
  u0.t = t
  
# Split mixed functions

  c0, mu0 = u0.split()

  c, mu   = u.split()

Would like to interpolate the final solution onto a new mesh which is ‘c and mu’

2

Please take some time to carefully format your question such that code snippets and mathematical formulae are correctly presented.

Furthermore construct a minimal working example as described here.

The more succinct your question, the more likely it is that people will be able to offer help.

3

Please would like to know how to interpolate the final solution (c and mu) onto a different mesh, i am using mixed formulation, i have my previous solution to be c0 and mu0 and my current solution is c and mu.

4

As i said in the previous post, we Need a minimal example that is executable by anyone on any computer. The code you have posted above does not have the necessary definitions to be executable.

7

This what i did for my error analysis but seems not to work and get error saying
TypeError: instance between mesh and mesh.

Error Analysis and Convergence

if (Nt > 1):
for l in range(1, len(ch)):
c_error = dot(ch[l-1]-ch[l], ch[l-1]-ch[l])*dx
c_error = sqrt(assemble(c_error))
mu_error = dot(muh[l-1]-muh[l], muh[l-1]-muh[l])*dx
mu_error = sqrt(assemble(mu_error))

    c_L2_error.append(c_error)# when dt is refined
    mu_L2_error.append(mu_error)# when dt is refined

for l in range(1, len(c_L2_error)):
c_rate = ln(c_L2_error[l-1]/c_L2_error[l])/ln(2)
c_L2_rate.append(c_rate)

mu_rate = ln(mu_L2_error[l-1]/mu_L2_error[l])/ln(2)
mu_L2_rate.append(mu_rate)

print (‘L2_error in c =’, c_L2_error)
print (‘L2_rate in c =’, c_L2_rate)

print (‘L2_error in mu =’, mu_L2_error)
print (‘L2_rate in mu =’, mu_L2_rate)

8

Please format your code with three ` on each side of your code
and make sure it is runnable.
This line c, mu = u.split(). is not complete.
Additionally, make the example as small as possible, removing all lines that are not needed for showing the issue (But the code has to be executable).

9

I believe its the formatting.
u=function(mesh_coarse)
c,mu=u.split()

should be in the same line.