Refactor adapter for clearer control flow

[BenjaminRodenberg]

fenics-adapter/fenicsadapter/fenicsadapter.py

Lines 244 to 248 in 1b8a278

	# continue FEniCS computation from checkpoint
	u_n.assign(self._u_cp) # set u_n to value of checkpoint
	t = self._t_cp
	n = self._n_cp
	self._interface.fulfilled_action(precice.action_read_iteration_checkpoint())

--> Create Function restore_solver_state_from_checkpoint

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Lines 250 to 252 in 1b8a278

	u_n.assign(u_np1)
	t = new_t = t + dt # todo the variables new_t, new_n could be saved, by just using t and n below, however I think it improved readability.
	n = new_n = n + 1

--> Create Function advance_solver_state

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Lines 255 to 261 in 1b8a278

	# continue FEniCS computation with u_np1
	# update checkpoint
	self._u_cp.assign(u_np1)
	self._t_cp = new_t
	self._n_cp = new_n
	self._interface.fulfilled_action(precice.action_write_iteration_checkpoint())
	precice_step_complete = True

--> Create Function save_solver_state_to_checkpoint

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Line 254 in 1b8a278

if self._interface.is_action_required(precice.action_write_iteration_checkpoint()):

--> add assertion after this line assert(not solver_state_has_been_restored_before), since this control flow is invalid.

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Line 233 in 1b8a278

self._interface.write_block_scalar_data(self._write_data_id, self._n_vertices, self._vertex_ids, self._write_data)

--> add if is_read_data_available():

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Line 235 in 1b8a278

self._interface.read_block_scalar_data(self._read_data_id, self._n_vertices, self._vertex_ids, self._read_data)

--> add if is_write_data_required():

---

fenics-adapter/fenicsadapter/fenicsadapter.py

Lines 282 to 289 in 1b8a278

	if self._interface.is_read_data_available():
	self._interface.read_block_scalar_data(self._read_data_id, self._n_vertices, self._vertex_ids, self._read_data)
	if self._interface.is_action_required(precice.action_write_iteration_checkpoint()):
	self._u_cp = u_n.copy(deepcopy=True)
	self._t_cp = t
	self._n_cp = n
	self._interface.fulfilled_action(precice.action_write_iteration_checkpoint())

is code duplication of

fenics-adapter/fenicsadapter/fenicsadapter.py

Line 235 in 1b8a278

self._interface.read_block_scalar_data(self._read_data_id, self._n_vertices, self._vertex_ids, self._read_data)

fenics-adapter/fenicsadapter/fenicsadapter.py

Lines 254 to 261 in 1b8a278

	if self._interface.is_action_required(precice.action_write_iteration_checkpoint()):
	# continue FEniCS computation with u_np1
	# update checkpoint
	self._u_cp.assign(u_np1)
	self._t_cp = new_t
	self._n_cp = new_n
	self._interface.fulfilled_action(precice.action_write_iteration_checkpoint())
	precice_step_complete = True

[BenjaminRodenberg]

Use the names from this flowchart: usage.pdf

[uekerman]

As discussed between @BenjaminRueth and me: The flowchart still has several inconsistencies compared to the adapter example in the wiki that we need to fix.

[BenjaminRodenberg]

Issue is closed by #59.