Program Mencari Determinan Menggunakan Kofaktor

/*
 * Matriks.java
 *
 * Created on January 23, 2011, 4:28 PM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

/**
 *
 * @author Mr. Miscall
 */
public class Matriks {
 protected int baris;
 protected int kolom;
 protected double[][] nilai;
 
 /*constructor -- Nilai dari matriks diset nol*/
        public Matriks(int baris, int koloms) {
  if (baris <= 0 || koloms <= 0) throw new IndexOutOfBoundsException();
  this.baris = baris;
  this.kolom = koloms;
  this.nilai = new double[baris][koloms];
  this.zero();
 }
 
 /*Full constructor -- Nilai dari matriks diset sesuai dengan nilai yang diberikan*/
        public Matriks(int baris, int koloms, double[][] nilai) {
  this(baris, koloms);
  this.set(nilai);
 }
        
        /*Prosedure Membuat Matriks Nol*/
 public void zero() {
  for (int i = 0; i < this.baris; i++) {
   for (int j = 0; j < this.kolom; j++) {
    this.nilai[i][j] = 0;
   }
  }
 }
        
        /*Prosedure Menset Nilai Matriks*/
 public void set(double[][] nilai) {
  if (nilai == null) return;
  int baris = nilai.length;
  if (baris == 0) return;
  for (int i = 0; i < baris && i < this.baris; i++) {
   double[] row = nilai[i];
   if (row != null) {
    int kolom = row.length;
    if (kolom != 0) {
     kolom = kolom > this.kolom ? this.kolom : kolom;
     System.arraycopy(row, 0, this.nilai[i], 0, kolom);
    }
   }
  }
 }
        
        /*Fungsi Mengambil SubMatriks*/
        public Matriks getSubMatriks(int row, int col) throws IndexOutOfBoundsException {
  if (this.baris == 1 && row == 0) throw new IndexOutOfBoundsException();
  if (this.kolom == 1 && col >= 0) throw new IndexOutOfBoundsException();
  
  int nRows = (row >= this.baris || row < 0) ? this.baris : this.baris - 1;
  int nCols = (col >= this.kolom || col < 0) ? this.kolom : this.kolom - 1;
  
  int a = 0;
  int b = 0;
  
  Matriks m = new Matriks(nRows, nCols);
  
  for (int i = 0; i < baris; i++) {
   if (i != row) {
    for (int j = 0; j < kolom; j++) {
     if (j != col) {
      m.nilai[a][b] = this.nilai[i][j];
      b++;
     }
    }
    a++;
    b = 0;
   }
  }
  return m;
 }
        
        /*Fungsi Rekursif Mencari Determinan Metode Cofactor*/
        public double determinant(){
  //untuk matriks bukan persegi
  if (this.baris != this.kolom) {System.out.print("Tidak bisa!! Jumlah baris harus sama dengan jumlah kolom."); return 0;}
  
  //untuk matriks 1x1
  if (this.baris == 1) return this.nilai[0][0];
  
  //untuk matriks 2x2
  if (this.baris == 2) return this.nilai[0][0] * this.nilai[1][1] - this.nilai[0][1] * this.nilai[1][0];
  
                //untuk matriks 3x3 ke atas
  double det = 0;
  for (int i = 0; i < baris; i++) {
   det += (i % 2 == 0 ? 1 : -1) * this.nilai[i][0] * this.getSubMatriks(i, 0).determinant();
  }
  return det;
 }
 
        public void cetakIsiMatriks() {
            System.out.println("Matriks =");
            for(int i=0; i < this.baris; i++){
                for(int j=0; j < this.kolom; j++){
                    System.out.print(this.nilai[i][j]+" ");
                }
                System.out.println();
            }
 }
        
 public static void main(String[] args){
            Matriks a = new Matriks(1, 1, new double[][] {{1}});
            a.cetakIsiMatriks();
            System.out.println("Determinan = "+a.determinant());
  
            Matriks b = new Matriks(2, 2, new double[][] {{1, 3}, {1, 1}});
            b.cetakIsiMatriks();
            System.out.println("Determinan = "+b.determinant());
  
            Matriks c = new Matriks(2, 1, new double[][] {{1}, {2}});
            c.cetakIsiMatriks();
            System.out.println("Determinan = "+c.determinant());
                
            Matriks d = new Matriks(3, 3, new double[][] {{1, 3, 1}, {1, 1, 2}, {2, 3, 4}});
            d.cetakIsiMatriks();
            System.out.println("Determinan = "+d.determinant());
            
            Matriks e = new Matriks(5, 5, new double[][] {{1, 1, 1, 1, 1}, {1, 2, 1, 2, 1}, {2, 3, 4, 3, 1}, {1, 1, 7, 5, 1},{1, 1, 1, 5, 1}});
            e.cetakIsiMatriks();
            System.out.println("Determinan = "+e.determinant());
    }
}