Update knn.py

knn.py

+def distance_matrix(Y , X):
+    #This function takes as parameters two matrices X and Y
+    dists = np.sqrt(np.sum(-2 * np.multiply(X, Y)+ np.multiply(Y, Y) + np.multiply(X, X)))
+    #dists is the euclidian distance between two matrices
+    return dists
+
+def knn_predict(dists, labels_train,k):
+