Question

我正在创建一个函数，允许我返回一个在整个人群中具有最佳适应度的Vector，知道健身是double值，我的函数并不总是返回具有最大适应度的右向量矢量!!

  private Vector globalbest(Vector allpop){
       allpop = allPopulation;
       Vector global =null;
       for(int i=0;i<allPopulation.size()-1;i++)
  {
    double m1 =(fitness((Vector) allpop.get(i+1)));
    double m2 =(fitness((Vector) allpop.get(i)));
    int i1 = Double.compare(m1,m2); // if i1 is positive then the first is greater 
      if( i1 > 0 ){
          global = null;
          global = (Vector) allpop.get(i+1); 
                  }

  }
   return global;
                                           }

希望你能找到错误！因为它真的让我感到不安和Thanx

Answer 1

以下是获取最大值的替代方法。

Vector v = new Vector();
for(int i=0;i<allPopulation.size();i++)
  {
    double m1 =(fitness((Vector) allpop.get(i)));         
    v.add(m1);    
  }

Double max= (Double)Collections.max(v);
Vector global = (Vector) allpop.get(v.indexOf(max));

Answer 2

你只是在比较allpop中的两个相邻向量，就像这段代码所做的那样

double m1 =(fitness((Vector) allpop.get(i+1)));
double m2 =(fitness((Vector) allpop.get(i)));

这仅适用于前两个向量（即第一个迭代），之后您应该将下一个向量与前两个向量中的最佳向量进行比较

试试这个

private Vector globalbest(Vector allpop){
   allpop = allPopulation;
   Vector global =null;
   double m1 =(fitness((Vector) allpop.get(1)));
   double m2 =(fitness((Vector) allpop.get(0)));
   int i1 = Double.compare(m1,m2); // if i1 is positive then the first is greater 
   if( i1 > 0 )
      global = (Vector) allpop.get(1); 
   else
      global = (Vector) allpop.get(0); 
   for(int i = 1;i<allPopulation.size()-1;i++)
   {
       m1 = (fitness((Vector) allpop.get(i)));
       double globalfitness = (fitness((Vector) global));
       int i1 = Double.compare(m1,globalfitness); //
       if( i1 > 0 )
           global = (Vector) allpop.get(i);  
   }
   return global;
}

编辑根据我的评论，您应该在方法中包含向量的类型定义，如此

 private Vector<Double> globalbest(Vector<Vector<Double>> allpop){...

这假设您的Vector allPopulation是双打向量，如果没有，则将Double更改为该类型。

函数比较java中的double值以获得最大值

2 个答案: