Added PLMP as an alternative technique to use; knn() is now exposed in the mp namespace.

1 files changed, 30 insertions, 0 deletions

diff --git a/knn.cpp b/knn.cpp
new file mode 100644
index 0000000..579a76f
--- /dev/null
+++ b/knn.cpp
@@ -0,0 +1,30 @@
+#include "mp.h"
+
+void mp::knn(const arma::mat &dmat, arma::uword i, arma::uword k, arma::uvec &nn, arma::vec &dist)
+{
+    arma::uword n = dist.n_rows;
+    double dmax = arma::datum::inf;
+    nn.fill(i);
+    dist.fill(dmax);
+    if (k > n) {
+        return;
+    }
+
+    const arma::vec &dvec = dmat.col(i);
+    for (arma::uword j = 0; j < n; j++) {
+        if (j == i || dvec[j] > dmax) {
+            continue;
+        }
+
+        arma::uword l;
+        for (l = 0; dist[l] < dvec[j] && l < k; l++);
+        for (arma::uword m = k - 1; m > l; m--) {
+            nn[m]   = nn[m - 1];
+            dist[m] = dist[m - 1];
+        }
+
+        nn[l] = j;
+        dist[l] = dvec[j];
+        dmax = dist[k - 1];
+    }
+}