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StringDistances.jl
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simplify pairwise

doc
matthieugomez 2020-12-30 14:39:18 +01:00
parent 15175976a2
commit f270e18310
1 changed files with 20 additions and 38 deletions
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src/pairwise.jl
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@ -1,9 +1,8 @@
@doc """
pairwise(dist::StringDistance, xs::AbstractVector; preprocess = nothing)
pairwise(dist::StringDistance, xs::AbstractVector, ys::AbstractVector; preprocess = nothing)
pairwise(dist::StringDistance, xs::AbstractVector, ys::AbstractVector = xs; preprocess = nothing)
Compute distances between all pairs of elements in `xs` and `ys` according to the
`StringDistance` `dist`.
`StringDistance` `dist`. Returns a matrix R such that `R[i, j]` corrresponds to the distance between `xs[i]` and `ys[j]`.
For AbstractQGramDistances preprocessing will be used either if `preprocess` is set
to true or if there are more than 5 elements in `xs`. Set `preprocess` to
@ -15,12 +14,12 @@ Both symmetric and asymmetric versions are available.
```julia-repl
julia> using StringDistances
julia> iter = ["New York", "Princeton"]
julia> pairwise(Levenshtein(), iter) # symmetric
julia> pairwise(Levenshtein(), iter)
2×2 Array{Float64,2}:
0.0 9.0
9.0 0.0
julia> iter2 = ["San Francisco"]
julia> pairwise(Levenshtein(), iter, iter2) # asymmetric
julia> pairwise(Levenshtein(), iter, iter2)
2×1 Array{Float64,2}:
12.0
10.0
@ -28,7 +27,7 @@ julia> pairwise(Levenshtein(), iter, iter2) # asymmetric
"""
Distances.pairwise
function Distances.pairwise(dist::StringDistance, xs::AbstractVector, ys::AbstractVector; preprocess = nothing)
function Distances.pairwise(dist::StringDistance, xs::AbstractVector, ys::AbstractVector = xs; preprocess = nothing)
T = result_type(dist, eltype(xs), eltype(ys))
if Missing <: Union{eltype(xs), eltype(ys)}
T = Union{T, Missing}
@ -37,21 +36,11 @@ function Distances.pairwise(dist::StringDistance, xs::AbstractVector, ys::Abstra
pairwise!(R, dist, xs, ys; preprocess = preprocess)
end
function Distances.pairwise(dist::StringDistance, xs::AbstractVector; preprocess = nothing)
T = result_type(dist, eltype(xs), eltype(xs))
if Missing <: eltype(xs)
T = Union{T, Missing}
end
R = Matrix{T}(undef, length(xs), length(xs))
pairwise!(R, dist, xs; preprocess = preprocess)
end
@doc """
pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector; preprocess = nothing)
pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector, ys::AbstractVector; preprocess = nothing)
pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector, ys::AbstractVector = xs; preprocess = nothing)
Compute distances between all pairs of elements in `xs` and `ys` according to the
`StringDistance` `dist` and write the result in `R`.
`StringDistance` `dist` and write the result in `R`. `R[i, j]` corrresponds to the distance between `xs[i]` and `ys[j]`.
For AbstractQGramDistances preprocessing will be used either if `preprocess` is set
to true or if there are more than 5 elements in `xs`. Set `preprocess` to
@ -59,30 +48,14 @@ false if no preprocessing should be used, regardless of length.
"""
Distances.pairwise!
function Distances.pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector, ys::AbstractVector; preprocess = nothing)
function Distances.pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector, ys::AbstractVector = xs; preprocess = nothing)
length(xs) == size(R, 1) || throw(DimensionMismatch("inconsistent length"))
length(ys) == size(R, 2) || throw(DimensionMismatch("inconsistent length"))
_asymmetric_pairwise!(R, dist, xs, ys; preprocess = preprocess)
end
function Distances.pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector; preprocess = nothing)
length(xs) == size(R, 1) || throw(DimensionMismatch("inconsistent length"))
length(xs) == size(R, 2) || throw(DimensionMismatch("inconsistent length"))
(dist isa SemiMetric) ?
((xs === ys) & (dist isa SemiMetric)) ?
_symmetric_pairwise!(R, dist, xs; preprocess = preprocess) :
_asymmetric_pairwise!(R, dist, xs, xs; preprocess = preprocess)
_asymmetric_pairwise!(R, dist, xs, ys; preprocess = preprocess)
end
function _preprocess(xs, dist::AbstractQGramDistance, preprocess)
if preprocess === nothing ? length(xs) >= 5 : preprocess
return map(x -> x === missing ? x : QGramSortedVector(x, dist.q), xs)
else
return xs
end
end
_preprocess(xs, dist::StringDistance, preprocess) = xs
function _symmetric_pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector; preprocess = nothing)
objs = _preprocess(xs, dist, preprocess)
for i in 1:length(objs)
@ -97,7 +70,7 @@ end
function _asymmetric_pairwise!(R::AbstractMatrix, dist::StringDistance, xs::AbstractVector, ys::AbstractVector; preprocess = nothing)
objsxs = _preprocess(xs, dist, preprocess)
objsys = _preprocess(ys, dist, preprocess)
objsys = xs === ys ? objsxs : _preprocess(ys, dist, preprocess)
for i in 1:length(objsxs)
Threads.@threads for j in 1:length(objsys)
R[i, j] = evaluate(dist, objsxs[i], objsys[j])
@ -105,3 +78,12 @@ function _asymmetric_pairwise!(R::AbstractMatrix, dist::StringDistance, xs::Abst
end
return R
end
function _preprocess(xs, dist::AbstractQGramDistance, preprocess)
if preprocess === nothing ? length(xs) >= 5 : preprocess
return map(x -> x === missing ? x : QGramSortedVector(x, dist.q), xs)
else
return xs
end
end
_preprocess(xs, dist::StringDistance, preprocess) = xs