use newer pattern

Author: Guy

README.md

@@ -132,6 +132,8 @@ Each distance corresponds to a distance type. The type name and the correspondin
 |  Chebyshev           |  chebyshev(x, y)     | max(abs(x - y)) |
 |  Minkowski           |  minkowski(x, y, p)  | sum(abs(x - y).^p) ^ (1/p) |
 |  Hamming             |  hamming(x, y)       | sum(x .!= y) |
+|  Rogers-Tanimoto     |  rogerstanimoto(x, y)| (2(ntf + nft)) / (2(ntf + nft) + ntt + nff) |
+|  Jaccard             |  jaccard(x, y)       | 1 - (sum(min(xi, yi)) / sum(max(xi, yi))) |
 |  CosineDist          |  cosine_dist(x, y)   | 1 - dot(x, y) / (norm(x) * norm(y)) |
 |  CorrDist            |  corr_dist(x, y)     | cosine_dist(x - mean(x), y - mean(y)) |
 |  ChiSqDist           |  chisq_dist(x, y)    | sum((x - y).^2 / (x + y)) |

src/metrics.jl

@@ -28,7 +28,7 @@ type JSDivergence <: SemiMetric end
 
 type SpanNormDist <: SemiMetric end
 
-typealias UnionMetrics @compat(Union{Euclidean, SqEuclidean, Chebyshev, Cityblock, Minkowski, Hamming, CosineDist, CorrDist, ChiSqDist, KLDivergence, JSDivergence, SpanNormDist})
+typealias UnionMetrics @compat(Union{Euclidean, SqEuclidean, Chebyshev, Cityblock, Minkowski, Hamming, Jaccard, RogersTanimoto, CosineDist, CorrDist, ChiSqDist, KLDivergence, JSDivergence, SpanNormDist})
 
 ###########################################################
 #
@@ -157,7 +157,7 @@ js_divergence(a::AbstractArray, b::AbstractArray) = evaluate(JSDivergence(), a,
 
 # SpanNormDist
 function eval_start(::SpanNormDist, a::AbstractArray, b::AbstractArray)
-    a[1] - b[1], a[1]- b[1]
+    a[1] - b[1], a[1] - b[1]
 end
 @compat @inline eval_op(::SpanNormDist, ai, bi)  = ai - bi
 @compat @inline function eval_reduce(::SpanNormDist, s1, s2)
@@ -248,46 +248,44 @@ end
 
 # Jaccard
 
-function evaluate(dist::Jaccard, a::AbstractVector, b::AbstractVector)
-    n = get_common_len(a, b)::Int
-    numerator = 0
-    denominator = 0
-    for i = 1:n
-        @inbounds ai = a[i]
-        @inbounds bi = b[i]
-        if ai > bi
-          numerator += bi
-          denominator += ai
-        else
-          numerator += ai
-          denominator += bi
-        end
-    end
-    1 - (numerator / denominator)
+@compat @inline eval_start(::Jaccard, a::AbstractArray, b::AbstractArray) = 0, 0
+@compat @inline function eval_op(::Jaccard, s1, s2)
+    denominator = max(s1, s2)
+    numerator = min(s1, s2)
+    numerator, denominator
 end
-
-jaccard(a::AbstractVector, b::AbstractVector) = evaluate(Jaccard(), a, b)
+@compat @inline function eval_reduce(::Jaccard, s1, s2)
+    a = s1[1] + s2[1]
+    b = s1[2] + s2[2]
+    a, b
+end
+@compat @inline eval_end(::Jaccard, a) = 1 - (a[1]/a[2])
+jaccard(a::AbstractArray, b::AbstractArray) = evaluate(Jaccard(), a, b)
 
 # Tanimoto
 
-function evaluate{T <: Bool}(dist::RogersTanimoto, a::AbstractVector, b::AbstractVector)
-    n = get_common_len(a, b)::Int
-    tt = 0
-    tf = 0
-    ft = 0
-    ff = 0
-    for i = 1:n
-        @inbounds tt += (a[i] && b[i])
-        @inbounds tf += (a[i] && !b[i])
-        @inbounds ft += (!a[i] && b[i])
-        @inbounds ff += (!a[i] && !b[i])
-    end
-    numerator = 2(tf + ft)
-    denominator = ntt + nff + 2(ntf + nft)
+@compat @inline eval_start(::RogersTanimoto, a::AbstractArray, b::AbstractArray) = 0, 0, 0, 0
+@compat @inline function eval_op(::RogersTanimoto, s1, s2)
+  tt = s1 && s2
+  tf = s1 && !s2
+  ft = !s1 && s2
+  ff = !s1 && !s2
+  tt, tf, ft, ff
+end
+@compat @inline function eval_reduce(::RogersTanimoto, s1, s2)
+    a = s1[1] + s2[1]
+    b = s1[2] + s2[2]
+    c = s1[3] + s2[3]
+    d = s1[4] + s1[4]
+    a, b, c, d
+end
+@compat @inline function eval_end(::RogersTanimoto, a)
+    numerator = 2(a[2] + a[3])
+    denominator = a[1] + a[4] + 2(a[2] + a[3])
     numerator / denominator
 end
+rogerstanimoto{T <: Bool}(a::AbstractArray{T}, b::AbstractArray{T}) = evaluate(RogersTanimoto(), a, b)
 
-rogerstanimoto(a::AbstractVector, b::AbstractVector) = evaluate(RogersTanimoto(), a, b)
 
 function pairwise!(r::AbstractMatrix, dist::CosineDist, a::AbstractMatrix, b::AbstractMatrix)
     m::Int, na::Int, nb::Int = get_pairwise_dims(r, a, b)

test/test_dists.jl

@@ -32,6 +32,10 @@ b = 2
 @test hamming(a, a) == 0
 @test hamming(a, b) == 1
 
+bt = [true, false, true]
+bf = [false, true, true]
+@test rogerstanimoto(bt, bt) == 0
+@test rogerstanimoto(bt, bf) == 4./5
 
 
 p = rand(12)
@@ -63,10 +67,6 @@ for (x, y) in (([4., 5., 6., 7.], [3., 9., 8., 1.]),
     @test_throws DimensionMismatch cosine_dist(1.:2, 1.:3)
     @test_approx_eq_eps cosine_dist(x, y) (1.0 - 112. / sqrt(19530.)) 1.0e-12
 
-    bt = [true, false, true]
-    bf = [false, true, true]
-    @test rogerstanimoto(bt, bt) == 0
-    @test rogerstanimoto(bt, bf) == 4./5
 
     @test_approx_eq_eps corr_dist(x, x) 0. 1.0e-12
     @test_approx_eq corr_dist(x, y) cosine_dist(x .- mean(x), vec(y) .- mean(y))