DofManager

The DofManager is a struct that keeps track of which dofs are unknown or constrained. This can work with simple or mixed finite element spaces of various types. It is a glorified book keeper.

A DofManager can be created as follows. First we must create functions for our variables of interest from their associated function spaces.

julia> using Exodus, FiniteElementContainersERROR: ArgumentError: Package Exodus not found in current path.
- Run `import Pkg; Pkg.add("Exodus")` to install the Exodus package.
julia> mesh = UnstructuredMesh("../../test/poisson/poisson.g")ERROR: UndefVarError: `UnstructuredMesh` not defined
julia> V = FunctionSpace(mesh, H1Field, Lagrange)ERROR: UndefVarError: `FunctionSpace` not defined
julia> u = VectorFunction(V, :u)ERROR: UndefVarError: `VectorFunction` not defined
julia> t = ScalarFunction(V, :t)ERROR: UndefVarError: `ScalarFunction` not defined
julia> f = FiniteElementContainers.GeneralFunction(u, t)ERROR: UndefVarError: `FiniteElementContainers` not defined

Now we can supply these variables to the DofManager which takes varargs as inputs

julia> dof = DofManager(f)ERROR: UndefVarError: `DofManager` not defined

The print methods for this struct show simple metadata about the current dofs for each possible function space.

A set of unknowns can be set up as follows

julia> field = create_unknowns(dof)ERROR: UndefVarError: `create_unknowns` not defined

We can create fields of the right size from the DofManager with the following methods

julia> field = create_field(dof)ERROR: UndefVarError: `create_field` not defined

These methods take the backend of dof into account to ensure that the fields or unknowns produced are on the same device, e.g. CPU/GPU if dof is on the CPU/GPU.

This struct is created with all dofs initially set as unknown. To modify the unknowns we can do the following

API

FiniteElementContainers.AbstractDofManager — Type

abstract type AbstractDofManager{IT<:Integer, IDs<:AbstractArray{IT<:Integer, 1}}

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FiniteElementContainers.DofManager — Type

struct DofManager{Condensed, IT, IDs<:AbstractArray{IT, 1}, Var<:FiniteElementContainers.AbstractFunction} <: FiniteElementContainers.AbstractDofManager{IT, IDs<:AbstractArray{IT, 1}}

dirichlet_dofs::AbstractVector
unknown_dofs::AbstractVector
var::FiniteElementContainers.AbstractFunction

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FiniteElementContainers.DofManager — Method

DofManager(
    var::FiniteElementContainers.AbstractFunction;
    use_condensed
) -> DofManager{_A, Int64, Vector{Int64}, <:FiniteElementContainers.AbstractFunction{S, F}} where {_A, S, F<:FunctionSpace}

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Base.length — Method

length(dof::DofManager) -> Any

Return the total lenth of dofs in the problem.

E.g. for an H1 space this will the number of nodes times the number of degrees of freedom per node.

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Base.size — Method

size(dof::DofManager, i::Int64) -> Any

size(dof, 1) returns the number of dofs per entity, and size(dof, 2) returns the number of entities.

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Base.size — Method

size(dof::DofManager) -> Tuple{Any, Any}

This returns (n_dofs, n_entities) where n_dofs is the number of dofs per entity (e.g. node) and n_entities is the number of entitities (e.g. node).

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FiniteElementContainers.create_field — Method

create_field(dof::DofManager) -> Any

Creates a field where typeof(field) <: AbstractField based on the variable dof was created with

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FiniteElementContainers.create_unknowns — Method

create_unknowns(dof::DofManager{false, IT, IDs, Var}) -> Any

Creates a vector of unknown dofs.

This specific method returns a vector equal in length to the length of the internally stored list of unknown dofs in dof.

This is used for solution techniques when vector/matrix rows are removed where dofs are fixed.

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FiniteElementContainers.create_unknowns — Method

create_unknowns(dof::DofManager{true, IT, IDs, Var}) -> Any

Creates a vector of unknown dofs.

This specific method returns a vector equal in length to the length of a field created by dof. E.g. all dofs are unknown.

This is used for solution techniques when vector/matrix rows are not removed where dofs are fixed.

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FiniteElementContainers.extract_field_unknowns! — Method

extract_field_unknowns!(
    Uu::AbstractVector{<:Number},
    dof::DofManager{false, IT, IDs, Var},
    U::FiniteElementContainers.AbstractField
)

Updates the entries of Uu with the unknown dofs in the field U.

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FiniteElementContainers.update_dofs! — Method

update_dofs!(
    dof::DofManager,
    dirichlet_dofs::AbstractVector{<:Integer}
)

Takes in a list of dof ids associated with dirichlet bcs and updates the internals of dof to reflect these.

NOTE: This clears all existing bcs in dof and starts fresh.

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FiniteElementContainers.update_field_unknowns! — Method

update_field_unknowns!(
    U::FiniteElementContainers.AbstractField,
    dof::DofManager,
    Uu::FiniteElementContainers.AbstractField
)

Takes in a field and updates the field

I think this one can be removed/deprecated

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FiniteElementContainers.update_field_unknowns! — Method

update_field_unknowns!(
    U::FiniteElementContainers.AbstractField,
    dof::DofManager,
    Uu::AbstractVector{<:Number}
)

Updates the unknowns of the field U based on the values of Uu.

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