fm_fem: Compute finite element matrices

Description

Compute finite element mass and structure matrices

Usage

fm_fem(mesh, order = 2, ...)
# S3 method for fm_mesh_1d
fm_fem(mesh, order = 2, ...)
# S3 method for fm_mesh_2d
fm_fem(mesh, order = 2, aniso = NULL, ...)
# S3 method for fm_tensor
fm_fem(mesh, order = 2, ...)
# S3 method for fm_collect
fm_fem(mesh, order = 2, ...)
# S3 method for fm_mesh_3d
fm_fem(mesh, order = 2, ...)

Value

fm_fem.fm_mesh_1d: A list with elements c0, c1, g1, g2, etc. When mesh$degree == 2, also g01, g02, and g12.

fm_fem.fm_mesh_2d: A list with elements c0, c1, g1, va, ta, and more if order > 1. When aniso is non-NULL, also g1aniso

matrices, etc.

fm_fem.fm_tensor: A list with elements cc, g1, g2.

fm_fem.fm_collect: A list with elements c0, c1, g1, g2, etc, and cc (c0 for every model except fm_mesh_1d with degree=2, for which it is c1). If the base type for the collection provides va and ta values, those are also returned.

fm_fem.fm_mesh_3d: A list with elements c0, c1, g1, g2, va, ta, and more if order > 2.

Arguments

mesh: fm_mesh_1d(), fm_mesh_2d(), or other supported mesh class object
order: integer; the maximum operator order
...: Currently unused
aniso: If non-NULL, a list(gamma, v). Calculates anisotropic structure matrices (in addition to the regular) for $\gamma$ and $v$ for an anisotropic operator $\nabla\cdot H \nabla$, where $H=\gamma I + v v^\top$. Currently (2023-08-05) the fields need to be given per vertex.

Examples

Run this code

names(fm_fem(fm_mesh_1d(1:4), order = 3))
names(fm_fem(fmexample$mesh, order = 3))

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