package org.jlinalg.demo;

import org.jlinalg.DoubleWrapper;
import org.jlinalg.FieldElement;
import org.jlinalg.Matrix;

/**
 * 
 * @author Andreas Keilhauer
 * 
 */
public class EigenvaluesDemo {

	public static void main(String[] argv) {
		DoubleWrapper d0, d1, d2, d3;
		d0 = new DoubleWrapper(0.0);
		d1 = new DoubleWrapper(1.0);
		d2 = new DoubleWrapper(2.0);
		d3 = new DoubleWrapper(3.0);

		// The eigenvalues of a diagonal matrix are always the diagonal entries:

		Matrix diagonalMatrix = new Matrix(new FieldElement[][] {
				{ d1, d0, d0 }, { d0, d2, d0 }, { d0, d0, d3 } });
		System.out.println("Diagonal Matrix: \n" + diagonalMatrix);
		System.out.println("All eigenvalues: " + diagonalMatrix.eig());

		// In general, the eigenvalues of a real matrix can be complex:

		Matrix m = new Matrix(new FieldElement[][] { { d1, d1.negate() },
				{ d1, d1 } });
		System.out.println("New matrix: \n" + m);
		System.out.println("All eigenvalues: " + m.eig());

	}
}