Fixed centering bug

src/kernelutilities.jl

@@ -5,8 +5,8 @@
 function kernelstatistics{T<:AbstractFloat}(K::Matrix{T})
     (n = size(K,1)) == size(K,2) || throw(DimensionMismatch("Kernel matrix must be square."))
     μ_κ = vec(sum(K,1))
-    μ_k = sum(κ)/(n^2)
-    broadcast!(/, κ, κ, n)
+    μ_k = sum(μ_κ)/(n^2)
+    broadcast!(/, μ_κ, μ_κ, n)
     return (μ_κ, μ_k)
 end
 
@@ -22,7 +22,7 @@ function center_symmetric!{T<:AbstractFloat}(KC::KernelCenterer{T}, K::Matrix{T}
     μ_κ = KC.mu_kappa
     length(μ_κ) == n || throw(DimensionMismatch("Kernel statistics do not match matrix."))
     for j = 1:n, i = 1:n
-        @inbounds K[i,j] += μ_k - 2*μ_κ[i]
+        @inbounds K[i,j] += μ_k - μ_κ[i] - μ_κ[j]
     end
     return K
 end

test/kernelutilities.jl

@@ -1,4 +1,4 @@
-n = 30
+n = 3
 m = 20
 p = 5
 
@@ -16,3 +16,36 @@ for T in FloatingPointTypes
     N = (C'W)*C
     @test_approx_eq N K
 end
+
+info("Testing ", MOD.kernelstatistics.env.name)
+for T in FloatingPointTypes
+    X = rand(T, n, n)
+    x, s = MOD.kernelstatistics(X)
+
+    @test_approx_eq x vec(mean(X,1))
+    @test_approx_eq s mean(X)
+end
+
+info("Testing ", MOD.KernelCenterer.name.name)
+for T in FloatingPointTypes
+    K = rand(T, n, n)
+
+    k, s = MOD.kernelstatistics(K)
+    KC = MOD.KernelCenterer(K)
+
+    @test_approx_eq k KC.mu_kappa
+    @test_approx_eq s KC.mu_k
+end
+
+info("Testing ", MOD.center_symmetric!.env.name)
+for T in FloatingPointTypes
+    X = rand(T, n, p)
+    K = X*transpose(X)
+    KC = MOD.KernelCenterer(K)
+    MOD.center_symmetric!(KC, K)
+
+    Xc = X .- mean(X,1)
+    Kc = Xc*transpose(Xc)
+
+    @test_approx_eq K Kc
+end