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 an instance of Message to an instance of Marginal. For Marginal itself it returns the input unchanged. This is an internal function and is not supposed to be used outside of ReactiveMP package.

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.