Sum-Product Networks in Julia

pkg> add SumProductNetworks

using SumProductNetworks

# Create a root sum node.
root = FiniteSumNode();

# Add two product nodes to the root.
add!(root, FiniteProductNode(), log(0.3)); # Use a weight of 0.3
add!(root, FiniteProductNode(), log(0.7)); # Use a weight of 0.7

# Add Normal distributions to the product nodes, i.e. leaves.
for prod in children(root)
    for d in 1:2 # Assume 2-D data
        add!(prod, UnivariateNode(Normal(), d));
    end
end

# Compile the constructed network to an SPN type
spn = SumProductNetwork(root);

# Print statistics on the network.
println(spn)

# Update the scope of all nodes, i.e. propagate the scope bottom-up.
updatescope!(spn)

# Evaluate the network on some data.
x = [0.8, 1.2];
logp = logpdf(spn, x)

# Access the stored log likelihood
llh = spn.info[:llh]

# Evaluate the network by marginalising out a RV.
x = [0.8, NaN]
logp = logpdf(spn, x)

# Save the network to a DOT file.
export_network(spn, "mySPN.dot")

using SumProductNetworks
using AxisArrays

N = 100
D = 2

x = rand(N, D)

# Create a root sum node.
root = FiniteSumNode{Float32}();

# Add two product nodes to the root.
add!(root, FiniteProductNode(), Float32(log(0.3))); # Use a weight of 0.3
add!(root, FiniteProductNode(), Float32(log(0.7))); # Use a weight of 0.7

# Add Normal distributions to the product nodes, i.e. leaves.
for prod in children(root)
    for d in 1:2 # Assume 2-D data
        add!(prod, UnivariateNode(Normal(), d));
    end
end

# Compile the constructed network to an SPN type
spn = SumProductNetwork(root);

# Update the scope of all nodes.
updatescope!(spn)

# Store the logpdf value for every node in the SPN.
llhvals = initllhvals(spn, x)

# Compute logpdf values for all nodes in the network.
logpdf!(spn, x, llhvals)

# Print the logpdf value for each leaf.
for node in spn.leaves
    println("logpdf at $(node.id) = $(llhvals[:,node.id])")
end

# Assign observations to their most likely child under a sum node.
function assignobs!(node::SumNode, observations::Vector{Int})
    j = argmax(llhvals[observations, map(c -> c.id, children(node))], dims = 2)

    # Set observations to the node.
    setobs!(node, observations)

    # Set observations for the children of the node.
    for k in length(node)
        setobs!(node[k], observations[findall(j .== k)])
    end

    # Get the parametric type of the sum node, i.e. Float32.
    T = eltype(node)

    # Update the weights of the root.
    w = map(c -> nobs(c) / nobs(node), children(node))
    for k in 1:length(node)
        logweights(node)[k] = map(T, log(w[k]))
    end
end

# Call assignment function for the root.
assignobs!(spn.root, collect(1:N))

# Abstract type hierarchy.
SPNNode
Node <: SPNNode
Leaf <: SPNNode
SumNode <: Node
ProductNode <: Node

# Node types.
FiniteSumNode() <: SumNode
FiniteProductNode() <: ProductNode
IndicatorNode(value::Int, scope::Int) <: Leaf
UnivariateNode(dist::UnivariateDistribution, scope::Int) <: Leaf
MultivariateNode(dist::MultivariateDistribution, scope::Vector{Int}) <: Leaf

SumProductNetwork(root::Node)

generate_spn(X::Matrix, algo::Symbol; params...)

# learnSPN algorithm by Gens et al.
generate_spn(X, :learnspn)

# Get all nodes of the network in topological order.
values(spn::SumProductNetwork)

# Get the ids of all nodes in the network.
keys(spn::SumProductNetwork)

# Number of nodes in the network.
length(spn::SumProductNetwork)

# Indexing using an id.
spn[id::Symbol]

# Locally normalize an SPN.
normalize!(spn::SumProductNetwork)

# Number of free parameters in the SPN.
complexity(spn::SumProductNetwork)

# Export the SPN to a DOT file.
export_network(spn::SumProductNetwork, filename::String)

# Draw a random sample for the SPN.
rand(spn::SumProductNetwork)

# Indexing an internal node returns the respective child.
node[i::Int]

# Add a child to an internal node (with or without weight).
add!(node::Node, child::SPNNode)
add!(node::Node, child::SPNNode, logw::Real)

# Remove a child from an internal node.
remove!(node::Node, childIndex::Int)

# The depth of the SPN rooted at the node.
depth(node::SPNNode)

# Get all children of a node.
children(node::Node)

# Get the number of children of node.
length(node::Node)

# Get all parents of a node.
parents(node::SPNNode)

# Has the node a weights field.
hasweights(node::Node)

# Get all weights of the node.
weights(node::Node) = exp.(logweights(node))

# Get all log weights of the node
logweights(node::Node)

# Is the SPN rooted at the node normalized?
isnormalized(node::SPNNode)

# Compute the log pdf.
logpdf(node::SPNNode, x::AbstractArray)

# Alternatively, you can call the object with some data.
node(x::AbstractArray)

# Compute the log pdf but use the passed parameters instead.
logpdf(node::Leaf, x::AbstractArray, p...)
logpdf(node::SumNode, x::AbstractArray; lw::AbstractVector=logweights(node))

# Draw a random sample from a node.
rand(node::SPNNode)

# Independence test by Margaritis and Thurn for discrete sets.
bmitest(X::Vector{Int}, Y::Vector{Int})

# Efficient projections onto the L 1-ball.
projectToPositiveSimplex!(q::AbstractVector{<:Real}; lowerBound = 0.0, s = 1.0)

# Construct a log likelihoods data-structure.
initllhvals(spn::SumProductNetwork, X::AbstractMatrix)