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Update the structure TreeSet #70

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79 changes: 77 additions & 2 deletions src/coloring.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -328,7 +328,7 @@ function acyclic_coloring(g::Graph, order::AbstractOrder)
end
end
end
return color, TreeSet(forest)
return color, TreeSet(forest, nvertices)
end

function _prevent_cycle!(
Expand Down Expand Up @@ -408,5 +408,80 @@ $TYPEDFIELDS
"""
struct TreeSet
"a forest of two-colored trees"
forest::DisjointSets{Tuple{Int,Int}}
trees::Vector{Vector{Tuple{Int,Int}}}
"???"
nodes::Vector{Vector{Int}}
"???"
stored_values::Vector{Float64}
end

function TreeSet(forest::DisjointSets, nvertices::Int)
# forest is a structure DisjointSets from DataStructures.jl
# - forest.intmap: a dictionary that maps an edge (i, j) to an integer k
# - forest.revmap: a dictionary that does the reverse of intmap, mapping an integer k to an edge (i, j)
# - forest.internal.ngroups: the number of trees in the forest
ntrees = forest.internal.ngroups

# vector of trees where each tree contains the indices of its edges
trees = [Int[] for i in 1:ntrees]

# dictionary that maps a tree's root to the index of the tree
roots = Dict{Int,Int}()

k = 0
for edge in forest.revmap
root_edge = find_root!(forest, edge)
root = forest.intmap[root_edge]
if !haskey(roots, root)
k += 1
roots[root] = k
end
index_tree = roots[root]
push!(trees[index_tree], forest.intmap[edge])
end

# vector of dictionaries where each dictionary stores the degree of each vertex in a tree
degrees = [Dict{Int,Int}() for k in 1:ntrees]
for k in 1:ntrees
tree = trees[k]
degree = degrees[k]
for edge_index in tree
i, j = forest.revmap[edge_index]
!haskey(degree, i) && (degree[i] = 0)
!haskey(degree, j) && (degree[j] = 0)
degree[i] += 1
degree[j] += 1
end
end

# depth-first search (DFS) traversal order for each tree in the forest
dfs_orders = [Vector{Tuple{Int,Int}}() for k in 1:ntrees]
for k in 1:ntrees
tree = trees[k]
degree = degrees[k]
while sum(values(degree)) != 0
for (t, edge_index) in enumerate(tree)
if edge_index != 0
i, j = forest.revmap[edge_index]
if (degree[i] == 1) || (degree[j] == 1) # leaf vertex
if degree[i] > degree[j] # vertex i is the parent of vertex j
i, j = j, i # ensure that i always denotes a leaf vertex
end
degree[i] -= 1 # decrease the degree of vertex i
degree[j] -= 1 # decrease the degree of vertex j
tree[t] = 0 # remove the edge (i,j)
push!(dfs_orders[k], (i, j))
end
end
end
end
end

# stored_values holds the sum of edge values for subtrees in a tree.
# For each vertex i, stored_values[i] is the sum of edge values in the subtree rooted at i.
stored_values = Vector{Float64}(undef, nvertices)

nodes = [[vertex for vertex in keys(degrees[k])] for k = 1:ntrees]

return TreeSet(dfs_orders, nodes, stored_values)
end
72 changes: 4 additions & 68 deletions src/decompression.jl
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Expand Up @@ -303,72 +303,8 @@ function decompress_aux!(
A .= zero(R)
S = get_matrix(result)
color = column_colors(result)

# forest is a structure DisjointSets from DataStructures.jl
# - forest.intmap: a dictionary that maps an edge (i, j) to an integer k
# - forest.revmap: a dictionary that does the reverse of intmap, mapping an integer k to an edge (i, j)
# - forest.internal.ngroups: the number of trees in the forest
forest = result.tree_set.forest
ntrees = forest.internal.ngroups

# vector of trees where each tree contains the indices of its edges
trees = [Int[] for i in 1:ntrees]

# dictionary that maps a tree's root to the index of the tree
roots = Dict{Int,Int}()

k = 0
for edge in forest.revmap
root_edge = find_root!(forest, edge)
root = forest.intmap[root_edge]
if !haskey(roots, root)
k += 1
roots[root] = k
end
index_tree = roots[root]
push!(trees[index_tree], forest.intmap[edge])
end

# vector of dictionaries where each dictionary stores the degree of each vertex in a tree
degrees = [Dict{Int,Int}() for k in 1:ntrees]
for k in 1:ntrees
tree = trees[k]
degree = degrees[k]
for edge_index in tree
i, j = forest.revmap[edge_index]
!haskey(degree, i) && (degree[i] = 0)
!haskey(degree, j) && (degree[j] = 0)
degree[i] += 1
degree[j] += 1
end
end

# depth-first search (DFS) traversal order for each tree in the forest
dfs_orders = [Vector{Tuple{Int,Int}}() for k in 1:ntrees]
for k in 1:ntrees
tree = trees[k]
degree = degrees[k]
while sum(values(degree)) != 0
for (t, edge_index) in enumerate(tree)
if edge_index != 0
i, j = forest.revmap[edge_index]
if (degree[i] == 1) || (degree[j] == 1) # leaf vertex
if degree[i] > degree[j] # vertex i is the parent of vertex j
i, j = j, i # ensure that i always denotes a leaf vertex
end
degree[i] -= 1 # decrease the degree of vertex i
degree[j] -= 1 # decrease the degree of vertex j
tree[t] = 0 # remove the edge (i,j)
push!(dfs_orders[k], (i, j))
end
end
end
end
end

# stored_values holds the sum of edge values for subtrees in a tree.
# For each vertex i, stored_values[i] is the sum of edge values in the subtree rooted at i.
stored_values = Vector{R}(undef, n)
@compat (; trees, nodes, stored_values) = result.tree_set
ntrees = length(trees)

# Recover the diagonal coefficients of A
for i in axes(A, 1)
Expand All @@ -379,12 +315,12 @@ function decompress_aux!(

# Recover the off-diagonal coefficients of A
for k in 1:ntrees
vertices = keys(degrees[k])
vertices = nodes[k]
for vertex in vertices
stored_values[vertex] = zero(R)
end

tree = dfs_orders[k]
tree = trees[k]
for (i, j) in tree
val = B[i, color[j]] - stored_values[i]
stored_values[j] = stored_values[j] + val
Expand Down