如何在Java中創建任意大小的單位矩陣？

Question

是否有一個實用程序可以在Java中創建指定大小的單位矩陣？

Answer 1

我建議Jama滿足您的所有矩陣需求。有一個電話生成identity matrix（請參閱identity method）。

Answer 2

嘗試Apache Commons Math for commonly used linear algebra：

// Set dimension to the size of the square matrix that you would like 
// Example, this will make a 3x3 matrix with ones on the diagonal and 
// zeros elsewhere. 
int dimension = 3; 
RealMatrix identity = RealMatrix.createRealIdentityMatrix(dimension); 

Answer 3

如果你只是想用一個二維數組來表示矩陣，沒有第三方庫：

public class MatrixHelper { 
    public static double[][] getIdentity(int size) { 
    double[][] matrix = new double[size][size]; 
    for(int i = 0; i < size; i++) matrix[i][i] = 1; 
    return matrix; 
    } 
} 

Answer 4

內存，有效的解決方案是創建一個類似如此：

public class IdentityMatrix{ 
    private int dimension; 

    public IdentityMatrix(int dimension){ 
      this.dimension=dimension 
    } 

    public double getValue(int row,int column){ 
      return row == column ? 1 : 0; 
    } 
}