WIP: Unverified non-euclidean metric support for Elkan

Author: PyDataBlog

src/elkan.jl

@@ -52,7 +52,7 @@ function kmeans!(alg::Elkan, containers, X, k, weights=nothing, metric=Euclidean
         calculate_centroids_movement(alg, containers, centroids, metric)
 
         # lower and ounds update, in paper it's steps 5 and 6
-        @parallelize n_threads ncol chunk_update_bounds(alg, containers, centroids)
+        @parallelize n_threads ncol chunk_update_bounds(alg, containers, centroids, metric)
 
         # Step 7, final assignment of new centroids
         centroids .= containers.centroids_new[end]
@@ -259,14 +259,32 @@ function calculate_centroids_movement(alg::Elkan, containers, centroids, metric)
 end
 
 
-function chunk_update_bounds(alg, containers, centroids, r, idx)
+function chunk_update_bounds(alg, containers, centroids, metric::Euclidean, r, idx)
     p = containers.p
     lb = containers.lb
     ub = containers.ub
     stale = containers.stale
     labels = containers.labels
     T = eltype(centroids)
-    # TODO: Add metric support with multiple dispatch
+
+    @inbounds for i in r
+        for j in axes(centroids, 2)
+            lb[j, i] = lb[j, i] > p[j] ? lb[j, i] + p[j] - T(2)*sqrt(abs(lb[j, i]*p[j])) : zero(T)
+        end
+        stale[i] = true
+        ub[i] += p[labels[i]] + T(2)*sqrt(abs(ub[i]*p[labels[i]]))
+    end
+end
+
+
+function chunk_update_bounds(alg, containers, centroids, metric::Metric, r, idx)
+    p = containers.p
+    lb = containers.lb
+    ub = containers.ub
+    stale = containers.stale
+    labels = containers.labels
+    T = eltype(centroids)
+    # TODO: Update the metric support for non eucledian metric
     @inbounds for i in r
         for j in axes(centroids, 2)
             lb[j, i] = lb[j, i] > p[j] ? lb[j, i] + p[j] - T(2)*sqrt(abs(lb[j, i]*p[j])) : zero(T)