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correction for NormalizedQGram

pull/1/head
matthieugomez 2015-10-25 11:55:15 -04:00
parent 99853255b8
commit 18fd1ab91c
2 changed files with 8 additions and 2 deletions
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4
src/normalized.jl
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@ -19,8 +19,8 @@ function evaluate{T <: Union{Hamming, Levenshtein, DamerauLevenshtein}}(
return distance / len2
end
function evaluate(normalized::Normalized{QGram}, s1::AbstractString, s2::AbstractString,
function evaluate{T <: QGram}(normalized::Normalized{T}, s1::AbstractString, s2::AbstractString,
len1::Integer, len2::Integer)
distance = evaluate(normalized.dist, s1, s2, len1, len2)
return distance / (len1 + len2 - 2 * normalized.dist.q - 2)
return distance / (max(0, len1 - normalized.dist.q + 1) + max(0, len2 - normalized.dist.q + 1))
end

6
test/distances.jl
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@ -51,10 +51,16 @@ using StringDistances, Base.Test
@test evaluate(QGram(1), "", "abc") == 3
@test evaluate(QGram(1), "abc", "cba") == 0
@test evaluate(QGram(1), "abc", "ccc") == 4
@test_approx_eq_eps evaluate(Normalized(QGram(1)), "", "abc") 1.0 1e-4
@test_approx_eq_eps evaluate(Normalized(QGram(1)), "abc", "cba") 0.0 1e-4
@test_approx_eq_eps evaluate(Normalized(QGram(1)), "abc", "ccc") 2/3 1e-4
@test_approx_eq_eps evaluate(Jaccard(1), "", "abc") 1.0 1e-4
@test_approx_eq_eps evaluate(Jaccard(1), "abc", "ccc") .666666 1e-4