我正在尝试为Java中的TSP设计2-opt本地搜索启发式,但我的算法似乎有缺陷。给定最近的邻居电路,它会以某种方式使电路变得更糟。最近的邻居:http://goo.gl/uI5X6; 10秒后2-opt:http://goo.gl/5AGJ1。我的代码如下。我的实现有什么问题?位置[]位置只是“图形”节点的列表,每个节点都与其他节点之间的纬度和经度以及距离计算。有缺陷的2-opt搜索实现?
public HamiltonianCircuit execute(Location[] locations) {
long startTime = System.currentTimeMillis();
while (true) {
for (int i = 0; i < locations.length; i++) {
for (int k = 0; k < locations.length; k++) {
if (System.currentTimeMillis() - startTime >= 10000) {
return new HamiltonianCircuit(locations);
}
Location a = locations[i];
Location b = locations[(i + 1) % locations.length];
Location c = locations[k];
Location d = locations[(k + 1) % locations.length];
double distanceab = a.distanceBetween(b);
double distancecd = c.distanceBetween(d);
double distanceac = a.distanceBetween(c);
double distancebd = b.distanceBetween(d);
double change = (distanceab + distancecd) -
(distanceac + distancebd);
if (change > 0) {
locations[k] = a;
locations[i] = c;
}
}
}
}
}