策略最小化换线:增加多线程计算

src/main/java/com/aps/service/Algorithm/OrderSortService.java

@@ -128,7 +128,7 @@ public class OrderSortService {
         }
 
         // 定义阈值：当订单数量小于等于这个值时，遍历所有起始点
-        int threshold = 5;
+        int threshold = 10;
 
         if (orders.size() <= threshold) {
             // 订单数量较少，遍历所有起始点
@@ -183,8 +183,7 @@ public class OrderSortService {
         }
 
         // 1. 生成多个初始解，选择最优的一个
-        List<Order> bestInitialSolution = null;
-        double bestInitialCost = Double.MAX_VALUE;
+
 
         // 尝试多个随机起始点
         Set<Integer> selectedIndices = new HashSet<>();
@@ -193,16 +192,24 @@ public class OrderSortService {
 
         while (selectedIndices.size() < maxAttempts) {
             int randomIndex = random.nextInt(orders.size());
-            if (selectedIndices.add(randomIndex)) {
-                List<Order> initialSolution= generateInitialSolution(ProductionDeepCopyUtil.deepCopyList(orders) ,randomIndex);
-
+            selectedIndices.add(randomIndex);
+        }
+        List<Map.Entry<List<Order>, Double>> initialSolutions = selectedIndices.parallelStream()
+                .map(index -> {
+                    List<Order> initialSolution = generateInitialSolution(ProductionDeepCopyUtil.deepCopyList(orders), index);
+                    double initialCost = calculateTotalChangeoverCost(initialSolution);
+                    return new AbstractMap.SimpleEntry<>(initialSolution, initialCost);
+                })
+                .collect(Collectors.toList());
 
-                double initialCost = calculateTotalChangeoverCost(initialSolution);
+        // 选择最优初始解
+        List<Order> bestInitialSolution = null;
+        double bestInitialCost = Double.MAX_VALUE;
 
-                if (initialCost < bestInitialCost) {
-                    bestInitialCost = initialCost;
-                    bestInitialSolution = initialSolution;
-                }
+        for (Map.Entry<List<Order>, Double> entry : initialSolutions) {
+            if (entry.getValue() < bestInitialCost) {
+                bestInitialCost = entry.getValue();
+                bestInitialSolution = entry.getKey();
             }
         }
 
@@ -214,24 +221,62 @@ public class OrderSortService {
         int maxIterations = 50;
         int iteration = 0;
 
+//        do {
+//            improved = false;
+//            List<Order> bestNeighbor = new ArrayList<>(currentSolution);
+//            double bestNeighborCost = currentCost;
+//
+//            // 遍历所有相邻订单对，尝试交换
+//            for (int i = 0; i < currentSolution.size() - 1; i++) {
+//                // 交换相邻订单
+//                List<Order> neighbor = new ArrayList<>(currentSolution);
+//                Collections.swap(neighbor, i, i + 1);
+//
+//
+//                double neighborCost = calculateTotalChangeoverCost2(neighbor);
+//
+//                // 如果交换后成本更低，更新最佳邻居
+//                if (neighborCost < bestNeighborCost) {
+//                    bestNeighbor = neighbor;
+//                    bestNeighborCost = neighborCost;
+//                    improved = true;
+//                }
+//            }
+//
+//            // 如果找到更优解，更新当前解
+//            if (improved) {
+//                currentSolution = bestNeighbor;
+//              //  assignChangeoverPriority(currentSolution);
+//                currentCost = bestNeighborCost;
+//            }
+//
+//            iteration++;
+//        } while (improved && iteration < maxIterations);
+
         do {
             improved = false;
             List<Order> bestNeighbor = new ArrayList<>(currentSolution);
             double bestNeighborCost = currentCost;
 
-            // 遍历所有相邻订单对，尝试交换
-            for (int i = 0; i < currentSolution.size() - 1; i++) {
-                // 交换相邻订单
-                List<Order> neighbor = new ArrayList<>(currentSolution);
-                Collections.swap(neighbor, i, i + 1);
-
-
-                double neighborCost = calculateTotalChangeoverCost2(neighbor);
+            // 并行处理邻域搜索
+            List<Order> finalCurrentSolution = currentSolution;
+            List<Map.Entry<List<Order>, Double>> neighbors = IntStream.range(0, currentSolution.size() - 1)
+                    .parallel()
+                    .mapToObj(i -> {
+                        // 交换相邻订单
+                        List<Order> neighbor = new ArrayList<>(finalCurrentSolution);
+                        Collections.swap(neighbor, i, i + 1);
+
+                        double neighborCost = calculateTotalChangeoverCost2(neighbor);
+                        return new AbstractMap.SimpleEntry<>(neighbor, neighborCost);
+                    })
+                    .collect(Collectors.toList());
 
-                // 如果交换后成本更低，更新最佳邻居
-                if (neighborCost < bestNeighborCost) {
-                    bestNeighbor = neighbor;
-                    bestNeighborCost = neighborCost;
+            // 找到最佳邻居
+            for (Map.Entry<List<Order>, Double> entry : neighbors) {
+                if (entry.getValue() < bestNeighborCost) {
+                    bestNeighbor = entry.getKey();
+                    bestNeighborCost = entry.getValue();
                     improved = true;
                 }
             }
@@ -239,13 +284,13 @@ public class OrderSortService {
             // 如果找到更优解，更新当前解
             if (improved) {
                 currentSolution = bestNeighbor;
-              //  assignChangeoverPriority(currentSolution);
                 currentCost = bestNeighborCost;
             }
 
             iteration++;
         } while (improved && iteration < maxIterations);
 
+
         return currentSolution;
     }
     /**