PointEvaluator

PointEvaluator(
    kernel,
    u_args,
    ops_args;
    ...
) -> PointEvaluator{Float64}
PointEvaluator(
    kernel,
    u_args,
    ops_args,
    sol;
    Tv,
    kwargs...
) -> PointEvaluator{Float64}

Construct a PointEvaluator object for evaluating operator expressions at arbitrary points in a finite element space.

A PointEvaluator can be used to evaluate one or more operator evaluations (e.g., function values, gradients) at arbitrary points, optionally postprocessed by a user-supplied kernel function. The evaluation is performed with respect to a given solution and its finite element basis.

After construction, the PointEvaluator must be initialized with a solution using initialize!. Evaluation at a point is then performed using evaluate! or evaluate_bary!.

Arguments

• kernel! (optional): Postprocessing function for operator evaluations. Should have the form kernel!(result, eval_args, qpinfo).
• oa_args: Array of operator argument tuples (source block tag, operator type).
• sol (optional): Solution object for immediate initialization.

Keyword arguments:

• resultdim: dimension of result field (default = length of operators). Default: 0

• params: array of parameters that should be made available in qpinfo argument of kernel function. Default: nothing

• name: name for operator used in printouts. Default: ''PointEvaluator''

• verbosity: verbosity level. Default: 0

Kernel Function Interface

kernel!(result, eval_args, qpinfo)

• result: Preallocated array to store the kernel output.
• eval_args: Array of operator evaluations at the current evaluation point.
• qpinfo: QPInfos struct with information about the current evaluation point.

Usage

After construction, call initialize! to prepare the evaluator for a given solution, then use evaluate! or evaluate_bary! to perform point evaluations.

function eval_func(PE::PointEvaluator)

Yields the function (result, x) -> evaluate!(result,PE,x).

function eval_func_bary(PE::PointEvaluator)

Yields the function (result, xref, item) -> evaluate_bary!(result,PE,xref,item).

function evaluate!(
	result,
	PE::PointEvaluator,
	x
	)

Evaluates the PointEvaluator at the specified coordinates x. (To do so it internally calls CellFinder to find the cell and the barycentric coordinates of x and calls evaluate_bary!.)

function evaluate_bary!(
	result,
	PE::PointEvaluator,
	xref, 
	item
	)

Evaluates the PointEvaluator at the specified reference coordinates in the cell with the specified item number.

function initialize!(
	O::PointEvaluator,
	sol;
	time = 0,
	kwargs...)

Initializes the given PointEvaluator for a specified solution (FEVector or vector of FEVectorBlocks).

This function prepares the PointEvaluator for evaluation by associating it with the provided solution vector. It sets up the necessary finite element basis evaluators, local-to-global transformations, and cell finder structures for the underlying grid.

Arguments

• O::PointEvaluator: The PointEvaluator instance to initialize.
• sol: The solution object (e.g., array of FEVectorBlocks) to be used for evaluations.

Keyword Arguments

• time: (default: 0) Time value to be passed to the quadrature point info structure.

  • resultdim: dimension of result field (default = length of operators). Default: 0

  • params: array of parameters that should be made available in qpinfo argument of kernel function. Default: nothing

  • name: name for operator used in printouts. Default: ''PointEvaluator''

  • verbosity: verbosity level. Default: 0

Notes

• This function must be called before using evaluate! or evaluate_bary! with the PointEvaluator.

Initializes the given PointEvaluator for a specified solution (FEVector or vector of FEVectorBlocks).

This function prepares the PointEvaluator for evaluation by associating it with the provided solution vector. It sets up the necessary finite element basis evaluators, local-to-global transformations, and cell finder structures for the underlying grid.

Arguments

• O::PointEvaluator: The PointEvaluator instance to initialize.
• sol: The solution object (e.g., array of FEVectorBlocks) to be used for evaluations.

Keyword Arguments

• time: (default: 0) Time value to be passed to the quadrature point info structure.

  • resultdim: dimension of result field (default = length of operators). Default: 0

  • params: array of parameters that should be made available in qpinfo argument of kernel function. Default: nothing

  • name: name for operator used in printouts. Default: ''PointEvaluator''

  • verbosity: verbosity level. Default: 0

Notes

• This function must be called before using evaluate! or evaluate_bary! with the PointEvaluator.