read_data = precice.read_data()
# Update the coupling expression with the new read data
precice.update_coupling_expression(coupling_expression, read_data)
dt.assign(np.min([fenics_dt, precice_dt]))
# Compute solution u^n+1, use bcs u_D^n+1, u^n and coupling bcs
solve(a == L, u_np1, bcs)
# Write data to preCICE according to which problem is being solved
if problem is ProblemType.DIRICHLET:
# Dirichlet problem reads temperature and writes flux on boundary to Neumann problem
determine_gradient(V_g, u_np1, flux)
precice.write_data(flux)
elif problem is ProblemType.NEUMANN:
# Neumann problem reads flux and writes temperature on boundary to Dirichlet problem
precice.write_data(u_np1)
precice_dt = precice.advance(dt(0))
if precice.is_action_required(precice.action_read_iteration_checkpoint()
): # roll back to checkpoint
u_cp, t_cp, n_cp = precice.retrieve_checkpoint()
u_n.assign(u_cp)
t = t_cp
n = n_cp
else: # update solution
u_n.assign(u_np1)
t += dt
if precice.is_action_required(precice.action_write_iteration_checkpoint()): # write checkpoint
precice.store_checkpoint(u_n, t, n)
read_data = precice.read_data()
# Update the coupling expression with the new read data
precice.update_coupling_expression(coupling_expression, read_data)
dt.assign(np.min([fenics_dt, precice_dt]))
# Compute solution
solve(a == L, u_np1, bcs)
# Dirichlet problem obtains flux from solution and sends flux on boundary to Neumann problem
fluxes = fluxes_from_temperature_full_domain(F_known_u, V, k)
precice.write_data(fluxes)
precice_dt = precice.advance(dt(0))
if precice.is_action_required(precice.action_read_iteration_checkpoint()): # roll back to checkpoint
u_cp, t_cp, n_cp = precice.retrieve_checkpoint()
u_n.assign(u_cp)
t = t_cp
n = n_cp
else: # update solution
u_n.assign(u_np1)
t += dt
n += 1
if precice.is_time_window_complete():
# if abs(t % dt_out) < 10e-5: # output if t is a multiple of dt_out
b_forces = b.copy(
) # b is the same for every iteration, only forces change
for ps in Forces_x:
ps.apply(b_forces)
for ps in Forces_y:
ps.apply(b_forces)
assert (b is not b_forces)
solve(A, u_np1.vector(), b_forces)
dt = Constant(np.min([precice_dt, fenics_dt]))
# Write new displacements to preCICE
u_delta = project(u_np1 - u_ref, V)
precice.write_data(u_delta)
# Call to advance coupling, also returns the optimum time step value
precice_dt = precice.advance(dt(0))
# Either revert to old step if timestep has not converged or move to next timestep
if precice.is_action_required(precice.action_read_iteration_checkpoint()
): # roll back to checkpoint
u_cp, t_cp, n_cp = precice.retrieve_checkpoint()
u_n.assign(u_cp)
t = t_cp
n = n_cp
else:
u_n.assign(u_np1)
t += float(dt)
n += 1