Using Jama to calculate eigenvalues/eigenvectors?

Question

I'm working on a small Java application that performs calculations on matrices. This is what I did for now to calculate the determinant and inverse of a square matrix. But I want to use the class Jama for the calculation of the eigenvalues ​​and eigenvectors, but I do not know how to use it, could anyone give me a hand? Thanks.

import java.util.Scanner;
import Jama.*;

public class matrix {
   public static void main(String[] args) {
      double[][] matrix;
      double det;
      int n;

      Scanner scanner = new Scanner(System.in);

      System.out.println("Dimension of the matrix: ");
      n = scanner.nextInt();

      matrix = new int[n][n];

      // insert values
      for (int i = 0; i < n; i++) {
         for (int j = 0; j < n; j++) {

            System.out.printf("Values: " + i + " - " + j);
            System.out.printf("\n");
            matrix[i][j] = scanner.nextDouble();

         }
      }

      // calculate determinant
      det = dete(matrix, n);
   }

   private static dete(double ai[][], int i) {
      double l = 0;
      if (i == 1)
         l = ai[0][0];
      else if (i == 2) {
         l = ai[0][0] * ai[1][1] - ai[0][1] * ai[1][0];
      } else {
         double ai1[][] = new double[i - 1][i - 1];
         for (int k = 0; k < i; k++) {
            for (int i1 = 1; i1 < i; i1++) {
               int j = 0;
               for (int j1 = 0; j1 < i; j1++)
                  if (j1 != k) {
                     ai1[i1 - 1][j] = ai[i1][j1];
                     j++;
                  }

            }

            if (k % 2 == 0)
               l += ai[0][k] * dete(ai1, i - 1);
            else
               l -= ai[0][k] * dete(ai1, i - 1);
         }

      }
      return l;
   }
}

Answer 1

You just have to do this -

Matrix mat = oldMatrix.eig();

Do not forget to include Jama.Matrix.EigenvalueDecomposition.

You can have a look here