Re: [firedrake] eigenvalue problems with SLEPc

7 Dec 2016

      On 07/12/16 15:57, Shipton, Jemma wrote:
...
Hi Francis,
Your code doesn't assign anything to em_real and em_imag.
...
# Find eigenvalues an eigenvectors
vr, vi = petsc_a.getVecs()
for i in range(nconv):
    lam = es.getEigenpair(i, vr, vi)
    print lam
    eval_real.append(lam.real)
    eval_imag.append(lam.imag)
u_real, eta_real = em_real.split()
    #u_imag, eta_imag = em_imag.split()
p = plot(eta_real)
    p.show()
Also, em_real is a MixedFunctionSpace, not a Function.

I think you want:

em_real, em_imag = Function(Z), Function(Z)

then you can do:

for i in range(nconv):
    with em_real.dat.vec as vr:
        with em_imag.dat.vec as vi:
            lam = es.getEigenpair(i, vr, vi)
    print lam
    u_real, eta_real = em_real.split()
    plot(eta_real)

Unfortunately we don't currently support plotting of vector-valued
Functions (u_real) in this example.  You could output them for
visualisation in paraview instead:

output = File("eigenmodes.pvd")

u_real, eta_real = em_real.split()
u_real.rename("R(u)")
eta_real.rename("R(eta)")
for i in range(nconv):
   ...
   output.write(u_real, eta_real, time=i)

LAwrence

Re: [firedrake] eigenvalue problems with SLEPc

Lawrence Mitchell