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fix conductance function and its test #43

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fix conductance function and its test #43

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d84c92c
fix conductance function and its test
Oct 5, 2020
dfed6fd
Merge branch 'pszufe:master' into master
Inazuma110 Jan 30, 2023
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13 changes: 7 additions & 6 deletions src/algorithms/conductance.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -5,20 +5,21 @@ Calculate unweighted hypergraph conductance of `subset`.
note: ∅ ⊊ `subset` ⊊ `1:nhv(h)`

For more information see `1. Introduction` at:
Generalizing the Hypergraph Laplacian via a Diffusion Processwith Mediators,
auhtors: T-H. Hubert Chan, Xhibin Liang.
Spectral Properties of Hypergraph Laplacian and Approximation Algorithms
auhtors: T-H. Hubert Chan, Anand Louis, Zhihao Gavin Tang, and Chenzi Zhang
"""
function conductance(h::Hypergraph, subset::Set{Int})::Float64
if isempty(subset) error("`subset` is not allowed empty.") end
if subset == Set(1:nhv(h)) error("`subset` is not allowed true subset of `h`.") end
subset2 = setdiff(Set(1:nhv(h)), subset)
wₛ = sum([length(gethyperedges(h, node)) for node in subset])
w∂s = 0
volS = sum([sum(values(gethyperedges(h, node))) for node in subset])
volV_S = sum([sum(values(gethyperedges(h, node))) for node in subset2])
cutS = 0
for he in 1:nhe(h)
he_vertices = keys(getvertices(h, he))
if isempty(intersect(he_vertices, subset)) continue end
if isempty(intersect(he_vertices, subset2)) continue end
w∂s += length(getvertices(h, he))
cutS += 1
end
return w∂s / wₛ
return cutS / min(volS, volV_S)
end
14 changes: 7 additions & 7 deletions test/runtests.jl
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Expand Up @@ -311,7 +311,7 @@ end;
@test typeof(randompartition(hg, 2)) == Vector{Set{Int}}
@test length(randompartition(hg, 2)) == 2
@test sort(vcat(collect.(randompartition(hg, 2))...))==1:nhv(hg)

hh = Hypergraph{Bool}(7,4)
hh[1,1] = true
hh[2,1:2] .= true
Expand Down Expand Up @@ -476,10 +476,10 @@ end;
h[4,3:4] .= 1
h[5,4] = 1
h[5,2] = 1
@test SimpleHypergraphs.conductance(h, Set(1:3)) == 5 / 5
@test SimpleHypergraphs.conductance(h, Set(1)) == 3 / 1
@test SimpleHypergraphs.conductance(h, Set([1, 4])) == 8 / 3
@test SimpleHypergraphs.conductance(h, Set(2:5)) == 3 / 8
@test SimpleHypergraphs.conductance(h, Set(1:3)) == 2 / 4
@test SimpleHypergraphs.conductance(h, Set(1)) == 1 / 1
@test SimpleHypergraphs.conductance(h, Set([1, 4])) == 3 / 3
@test SimpleHypergraphs.conductance(h, Set(2:5)) == SimpleHypergraphs.conductance(h, Set(1))
h = Hypergraph{Int}(6, 7)
h[1:3, 1] .= 1
h[1:2, 2] .= 1
Expand All @@ -489,8 +489,8 @@ end;
h[4:6, 5] .= 1
h[4:5, 6] .= 1
h[5:6, 7] .= 1
@test SimpleHypergraphs.conductance(h, Set(1:3)) == 2 / 8
@test SimpleHypergraphs.conductance(h, Set([1, 4])) == 14 / 6
@test SimpleHypergraphs.conductance(h, Set(1:3)) == 1 / 8
@test SimpleHypergraphs.conductance(h, Set([1, 4])) == 6 / 6
@test_throws ErrorException SimpleHypergraphs.conductance(h, Set{Int}())
@test_throws ErrorException SimpleHypergraphs.conductance(h, Set(1:nhv(h)))
end;
Expand Down