added tests. fixed some bugs

Author: ajinkya-k

src/LinearAlgebra.jl

@@ -130,6 +130,10 @@ export
     lyap,
     mul!,
     norm,
+    lpdist,
+    l1dist,
+    euclidean,
+    l2dist,
     normalize!,
     normalize,
     nullspace,

src/generic.jl

@@ -907,6 +907,8 @@ function _lpunnorm(x::T, y::T, fn) where {T}
     for i in eachindex(x,y)
         @inbounds r += fn(x[i] - y[i])
     end
+
+    return r
 end
 
 
@@ -940,7 +942,7 @@ function lpdist(x::T, y::T, p::Real) where {T <: AbstractVector}
     if p == Inf
         r = 0.0
         for i in eachindex(x,y)
-            @inbounds r = max(x[i] - y[i], r)
+            @inbounds r = max(abs(x[i] - y[i]), r)
         end
         return r
     elseif iszero(p)

test/generic.jl

@@ -837,4 +837,20 @@ end
     end
 end
 
+@testset "distance functions" begin
+    x = [1., 2., 3.]; y = [1., 2.1, 3.4]
+    @test lpdist(x, y, 1) ≈ norm(x .- y, 1)
+    @test lpdist(x, y, 2) ≈ norm(x .- y, 2)
+    @test lpdist(x, y, 4) ≈ norm(x .- y, 4)
+    @test lpdist(x, y, 3.5) ≈ norm(x .- y, 3.5)
+    @test euclidean(x, y) ≈ norm(x .- y, 2)
+    @test l2dist(x, y) ≈ norm(x .- y, 2)
+    @test l1dist(x, y) ≈ norm(x .- y, 1)
+    @test lpdist(x, y, 0) ≈ norm(x .- y, 0)
+    @test lpdist(x, y, Inf) ≈ norm(x .- y, Inf)
+    @test_throws DomainError lpdist(x, y, -1)
+    @test_throws DomainError lpdist(x, y, -0.5)
+    @test_throws DimensionMismatch lpdist(x, [1.5, 2.0, 2.0, 3.1], 1)
+end
+
 end # module TestGeneric