Expose RemotePointEvaluation parameters in non-nested multigrid

[fdrmrc]

...through an AdditionalData struct.

[fdrmrc]

In addition to the arguments needed by the constructor of RemotePointEvaluation, I've added an additional boolean, enfroce_all_points_found, that allows to throw if not all points have been found after the search procedure. Ultimately, it calls the RPE::all_points_found().

To give more context, this PR is motivated by the fact that some boundary points may not be picked up due to floating point arithmetic in certain situations (for instance when one has neumann boundary conditions), leading to dramatic effects on the number of required iterations. This issue can be solved by simply tweaking the tolerance parameter, and this is what the present PR allows.

[peterrum]

I would write the text more general, since we plan to add more parameters.

[peterrum]

Suggested change

	* the documentation of RemotePointEvaluation. The last boolean parameter, @p enf_all_points_found is true by defaults and
	* the documentation of RemotePointEvaluation. The last Boolean parameter,
	* @p enf_all_points_found is true by defaults and

[peterrum]

Not needed.

[peterrum]

Not needed.

[peterrum]

Suggested change

	const bool enf_all_points_found = true)
	const bool enforce_all_points_found = true)

[peterrum]

The change to shared_ptr is not needed!?

[fdrmrc]

Sure, it was a leftover from debugging. Fixed, thanks

[peterrum]

Suggested change

	rpe->all_points_found(),
	!additional_data.enforce_all_points_found || rpe->all_points_found(),

[peterrum]

Looks good. Just some minor documentation changes.

[peterrum]

Normally, we described these parameters closer to the parameters. See

dealii/include/deal.II/lac/solver_gmres.h

Lines 197 to 261 in dfb4350

	/**
	* Standardized data struct to pipe additional data to the solver.
	*/
	struct AdditionalData
	{
	/**
	* Constructor. By default, set the number of temporary vectors to 30,
	* i.e. do a restart every 28 iterations. Also set preconditioning from
	* left, the residual of the stopping criterion to the default residual,
	* and re-orthogonalization only if necessary. Also, the batched mode with
	* reduced functionality to track information is disabled by default.
	*/
	explicit AdditionalData(
	const unsigned int max_n_tmp_vectors = 30,
	const bool right_preconditioning = false,
	const bool use_default_residual = true,
	const bool force_re_orthogonalization = false,
	const bool batched_mode = false,
	const LinearAlgebra::OrthogonalizationStrategy
	orthogonalization_strategy =
	LinearAlgebra::OrthogonalizationStrategy::modified_gram_schmidt);
	/**
	* Maximum number of temporary vectors. This parameter controls the size
	* of the Arnoldi basis, which for historical reasons is
	* #max_n_tmp_vectors-2. SolverGMRES assumes that there are at least three
	* temporary vectors, so this value must be greater than or equal to three.
	*/
	unsigned int max_n_tmp_vectors;
	/**
	* Flag for right preconditioning.
	*
	* @note Change between left and right preconditioning will also change
	* the way residuals are evaluated. See the corresponding section in the
	* SolverGMRES.
	*/
	bool right_preconditioning;
	/**
	* Flag for the default residual that is used to measure convergence.
	*/
	bool use_default_residual;
	/**
	* Flag to force re-orthogonalization of orthonormal basis in every step.
	* If set to false, the solver automatically checks for loss of
	* orthogonality every 5 iterations and enables re-orthogonalization only
	* if necessary.
	*/
	bool force_re_orthogonalization;
	/**
	* Flag to control whether a reduced mode of the solver should be
	* run. This is necessary when running (several) SolverGMRES instances
	* involving very small and cheap linear systems where the feedback from
	* all signals, eigenvalue computations, and log stream are disabled.
	*/
	bool batched_mode;
	/**
	* Strategy to orthogonalize vectors.
	*/
	LinearAlgebra::OrthogonalizationStrategy orthogonalization_strategy;
	};

.

[peterrum]

Could you break the line?

[peterrum]

Thanks!