Marginal implementation

Marginal(data, is_clamped, is_initial, addons)

An implementation of a marginal in variational message passing framework.

Arguments

• data::D: marginal always holds some data object associated with it, which is usually a probability distribution
• is_clamped::Bool, specifies if this marginal was the result of constant computations (e.g. clamped constants)
• is_initial::Bool, specifies if this marginal was used for initialization
• addons::A, specifies the addons of the marginal, which may carry extra bits of information, e.g. debug information, memory, etc.

Example

julia> distribution = Gamma(10.0, 2.0)
Distributions.Gamma{Float64}(α=10.0, θ=2.0)

julia> message = Marginal(distribution, false, true, nothing)
Marginal(Distributions.Gamma{Float64}(α=10.0, θ=2.0))

julia> mean(message) 
20.0

julia> getdata(message)
Distributions.Gamma{Float64}(α=10.0, θ=2.0)

julia> is_clamped(message)
false

julia> is_initial(message)
true

getdata(marginal::Marginal)

Returns data associated with the marginal.

is_clamped(marginal::Marginal)

Checks if marginal is clamped or not.

See also: is_initial

is_initial(marginal::Marginal)

Checks if marginal is initial or not.

See also: is_clamped

getaddons(marginal::Marginal)

Returns addons associated with the marginal.

as_marginal(any)

A function that converts any to an instance of Marginal.

to_marginal(any)

Transforms an input to a proper marginal distribution. Called inside as_marginal. Some nodes do not use Distributions.jl, but instead implement their own equivalents for messages for better efficiency. Effectively to_marginal is needed to convert internal effective implementation to a user-friendly equivalent (e.g. from Distributions.jl). By default does nothing and returns its input, but some nodes may override this behaviour (see for example Wishart and InverseWishart).

Note: This function is a part of the private API and is not intended to be used outside of the ReactiveMP package.