From 6c2208c3ada6cac94fa9e9f3496c106c433acda4 Mon Sep 17 00:00:00 2001
From: Yay295 <Yay295@users.noreply.github.com>
Date: Mon, 16 Jul 2018 23:50:13 -0500
Subject: [PATCH] remove redundant code

`computeInitialFeasibleSolution()` just gets the minimum value from each row and puts them in `labelByJob`. However, `computeInitialFeasibleSolution()` is only called once, right after calling `reduce()`, so the minimum value in each row is zero. Since `labelByJob` is already zero, this does nothing.

Likewise in `greedyMatch()`, `labelByWorker` and `labelByJob` are filled with zero's, so subtracting them does nothing.
---
 .../optimization/HungarianAlgorithm.java      | 30 ++++---------------
 1 file changed, 6 insertions(+), 24 deletions(-)

diff --git a/src/main/java/blogspot/software_and_algorithms/stern_library/optimization/HungarianAlgorithm.java b/src/main/java/blogspot/software_and_algorithms/stern_library/optimization/HungarianAlgorithm.java
index 2819188..50fef47 100755
--- a/src/main/java/blogspot/software_and_algorithms/stern_library/optimization/HungarianAlgorithm.java
+++ b/src/main/java/blogspot/software_and_algorithms/stern_library/optimization/HungarianAlgorithm.java
@@ -101,24 +101,6 @@ public HungarianAlgorithm(double[][] costMatrix) {
     Arrays.fill(matchWorkerByJob, -1);
   }
 
-  /**
-   * Compute an initial feasible solution by assigning zero labels to the
-   * workers and by assigning to each job a label equal to the minimum cost
-   * among its incident edges.
-   */
-  protected void computeInitialFeasibleSolution() {
-    for (int j = 0; j < dim; j++) {
-      labelByJob[j] = Double.POSITIVE_INFINITY;
-    }
-    for (int w = 0; w < dim; w++) {
-      for (int j = 0; j < dim; j++) {
-        if (costMatrix[w][j] < labelByJob[j]) {
-          labelByJob[j] = costMatrix[w][j];
-        }
-      }
-    }
-  }
-
   /**
    * Execute the algorithm.
    * 
@@ -129,11 +111,10 @@ protected void computeInitialFeasibleSolution() {
   public int[] execute() {
     /*
      * Heuristics to improve performance: Reduce rows and columns by their
-     * smallest element, compute an initial non-zero dual feasible solution and
-     * create a greedy matching from workers to jobs of the cost matrix.
+     * smallest element and create a greedy matching from workers to jobs of
+     * the cost matrix.
      */
     reduce();
-    computeInitialFeasibleSolution();
     greedyMatch();
 
     int w = fetchUnmatchedWorker();
@@ -244,9 +225,10 @@ protected int fetchUnmatchedWorker() {
   protected void greedyMatch() {
     for (int w = 0; w < dim; w++) {
       for (int j = 0; j < dim; j++) {
-        if (matchJobByWorker[w] == -1 && matchWorkerByJob[j] == -1
-            && costMatrix[w][j] - labelByWorker[w] - labelByJob[j] == 0) {
-          match(w, j);
+        if (matchJobByWorker[w] == -1 &&
+            matchWorkerByJob[j] == -1 &&
+            costMatrix[w][j] == 0) {
+          match(w,j);
         }
       }
     }