C++ equivalent of E.vector() = ev_r

variational formulation
1

I have a working Python code for Eigenmode analysis. I use a SLEPc Eigensolver, solve modes and export the result to a file.

Python code <<
tm = dolfin.SLEPcEigenSolver(S_tm, T_tm)
tm.solve(modes)

# get Eigen pair
k_r, k_i, ev_r, ev_i = tm.get_eigenpair(0)

E = dolfin.Function(V)   # V is my functionspace

E.vector()[:] = ev_r

# Exporting the file
file = dolfin.File("out.pvd")
file << E

In C++, it is almost the same.

C++ Code <<
dolfin::SLEPcEigenSolver tm(S_tm, T_tm);

tm.solve(5);
double kr, ki;

dolfin::Vector ev_i;
dolfin::Vector ev_r;

tm.get_eigenpair(k_r, k_i, ev_r, ev_i, 0);

dolfin::Function E;

But I couldn’t find how we can assign the Vector result (ev_r) of the get_eigenpair() method to a dolfin::Function (E)

2

Hi,
I have found a way to do it.

auto ev_r = std::make_shared<dolfin::Vector>();
dolfin::Vector ev_i();

 // get eigenpair
 tm.get_eigenpair(k_r, k_c, *ev_r, ev_i, 0);
    
 dolfin::Function E(V, ev_r);
 dolfin::File file("out.pvd");
 file << E;