通用稀疏矩阵加法 [英] Generic sparse matrix addition

问题描述

我有一个任务，我应该在通用稀疏矩阵上完成实现。我卡在添加部分。矩阵只会支持数字，所以我已经扩展数字希望我可以添加数字，这是错误的。数据结构不是一个数组，它基本上是2个链表。 （一个用于行，一个用于列）以下是有问题的代码：

  public MatrixSparse <？扩展Number> （int i = 0; i< r.length; i ++）{$ b（））的加法（MatrixSparse< ;? extends Number> A，MatrixSparse<？extends Number> B，MatrixSparse< （i，j）和B（i，j）之和的$ b（int j = 0; j  // set我错误
 //+是未定义的类型捕获＃2-？等等。
 result.set（i，j，（A.get（i，j）+ B.get（i，j）））; 
} 
} 
返回结果; 
} 
  

以及类头+类变量：

  class MatrixSparse< T extends Number> {
 final Links r []; 
最终链接c []; 
 final int rows，columns; 
 final T zero; 
  

关于如何实现这个add方法的建议？

 < （（整数）paramLeft）.intValue（）+（（整数）paramRight）.intValue（））; code> if（paramLeft instanceof Integer）{
 return new Integer 
} elseif（paramLeft instanceof Double）{
 .... 
} 
  

I have an assignment where Im supposed to finish the implementation on a generic sparse matrix. Im stuck on the addition part. The matrix is only going to support numbers so I had it extend Number hoping I could then add the numbers, thats wrong. The data structure is NOT an array, it is essentially 2 linked lists. (one for rows and one for columns) Here is the code in question:

public MatrixSparse<? extends Number> addition(MatrixSparse<? extends Number> A, MatrixSparse<? extends Number> B, MatrixSparse<? extends Number> result) {
    for (int i = 0; i < r.length; i++) {
        for(int j = 0; j < c.length; j++) {
            // set (i, j) to the sum of A(i,j) and B(i,j) is giving me an error
            // "+" is undefined for type capture#2-? etc.
            result.set(i, j, (A.get(i, j) + B.get(i, j)));
        }
    }
    return result;
}

and the class header + class variables:

class MatrixSparse<T extends Number> { 
final Links r[]; 
final Links c[];
final int rows, columns; 
final T zero; 

any suggestions about how to implement this add method?

解决方案

Treating then that as a mental/school exercise: You cannot add two generics together with "+" operator - operators are not "genericable" and you cannot overload them in Java (pretty much different than C++) and auto-boxing does not help. The only thing you can do I think is to write a generic T add(T paramLeft,T paramRight) in your Matrix and do something like that:

if (paramLeft instanceof Integer) {
     return new Integer(((Integer)paramLeft).intValue()+ ((Integer)paramRight).intValue());
} elseif (paramLeft instanceof Double) { 
     ....
}

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