R: Compute mapping matrix between mesh function space and points

fm_basis {fmesher}

R Documentation

Compute mapping matrix between mesh function space and points

Description

Computes the basis mapping matrix between a function space on a mesh, and locations.

Usage

fm_basis(x, ...)

## Default S3 method:
fm_basis(x, loc, ...)

## S3 method for class 'fm_mesh_1d'
fm_basis(x, loc, weights = NULL, derivatives = NULL, ...)

## S3 method for class 'fm_mesh_2d'
fm_basis(x, loc, weights = NULL, derivatives = NULL, ...)

## S3 method for class 'inla.mesh.1d'
fm_basis(x, loc, ...)

## S3 method for class 'inla.mesh'
fm_basis(x, loc, ...)

## S3 method for class 'fm_evaluator'
fm_basis(x, ...)

## S3 method for class 'fm_tensor'
fm_basis(x, loc, weights = NULL, ...)

Arguments

`x`	An object supported by the `fm_evaluator()` class
`...`	Currently unused
`loc`	A set of points of a class supported by `fm_evaluator(x, loc = loc)`
`weights`	Optional weight vector to apply (from the left, one weight for each row of the basis matrix)
`derivatives`	If non-NULL and logical, return a list, optionally including derivative matrices.

Value

A sparseMatrix

For fm_mesh_1d, a matrix, or if derivatives is TRUE, a list with elements

`A`	The projection matrix, `⁠u(loc_i)=sum_j A_ij w_i⁠`
`d1A`, `d2A`	Derivative weight matrices, `⁠du/dx(loc_i)=sum_j dx_ij w_i⁠`, etc.

For fm_mesh_2d, a matrix, or if derivatives is TRUE, a list with elements

`A`	The projection matrix, `⁠u(loc_i)=sum_j A_ij w_i⁠`
`dx`, `dy`, `dz`	Derivative weight matrices, `⁠du/dx(loc_i)=sum_j dx_ij w_i⁠`, etc.

For fm_tensor, a matrix

Examples

# Compute basis mapping matrix
str(fm_basis(fmexample$mesh, fmexample$loc))