java/matice.java

   1 import java.util.Random;
   2 import java.text.NumberFormat;
   3 import java.lang.Math;
   4 import java.io.*;
   5
   6 /** Class representing matrix with methods for matrix algebra
   7  * Copylefted by: Harvie 2oo9 ( http://blog.harvie.cz/ )
   8  * @author      Thomas Harvie Mudrunka (mudruto1)
   9  * @version     1.0
  10  */
  11
  12 class Matrix implements Serializable {
  13         public float[][] matrix;
  14         public final int x, y;
  15         private Random rnd = new Random();
  16
  17         /** Construct new zero matrix described by (rows,cols) */
  18         Matrix(int i, int j) {
  19                 x = i;
  20                 y = j;
  21                 matrix = new float[x][y];
  22                 for(i = 0;i < x;i++) for(j = 0;j < y;j++) matrix[i][j] = 0;
  23         }
  24
  25         /** Construct new matrix from (2d_array) */
  26         Matrix(float[][] m) {
  27                 x = m.length;
  28                 y = m[0].length;
  29                 matrix = m;
  30         }
  31
  32         /** Return matrix as multiline String ready to output */
  33         public String toString() {
  34                 String out = new String("");
  35                 for(int i = 0;i < x;i++) {
  36                         out += "|\t";
  37                         for(int j = 0;j < y;j++) out += (NumberFormat.getInstance().format(matrix[i][j])+"\t");
  38                         out += "|\n";
  39                 }
  40                 return out;
  41         }
  42
  43         /** Print matrix to console */
  44         public void print() {
  45                 System.out.println(this.toString());
  46         }
  47
  48         /** Randomize matrix with numbers x, where: 0 <= x < max */
  49         public void randomize(int max) {
  50                 for(int i = 0;i < x;i++) for(int j = 0;j < y;j++) matrix[i][j] = rnd.nextInt(max);
  51         }
  52
  53         /** Compare size of this and another matrix */
  54         public boolean compatible(Matrix m) {
  55                 if(m.x == this.x && m.y == this.y) return true;
  56                 System.err.println("Cannot add/subtract/multiply two matrices with different sizes!");
  57                 return false;
  58         }
  59
  60         /** Add another matrix to this and return result */
  61         public Matrix add(Matrix m) {
  62                 if(!compatible(m)) return null;
  63                 Matrix o = new Matrix(x,y);
  64                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] += this.matrix[i][j];
  65                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] += m.matrix[i][j];
  66                 return o;
  67         }
  68
  69         /** Subtract another matrix from this and return result */
  70         public Matrix subtract(Matrix m) {
  71                 if(!compatible(m)) return null;
  72                 Matrix o = new Matrix(x,y);
  73                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] += this.matrix[i][j];
  74                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] -= m.matrix[i][j];
  75                 return o;
  76         }
  77
  78         /** Scalar-multiply this matrix by another one and return result */
  79         public Matrix multiply(Matrix m) {
  80                 if(!compatible(m)) return null;
  81                 Matrix o = new Matrix(x,y);
  82                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] += this.matrix[i][j];
  83                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) o.matrix[i][j] *= m.matrix[i][j];
  84                 return o;
  85         }
  86
  87         /** Matrix-multiply this matrix by another one and return result */
  88         public Matrix mmultiply(Matrix m) {
  89                 if(this.y != m.x) {
  90                         System.err.println("Cannot multiply those two matrices!");
  91                         return null;
  92                 }
  93                 Matrix o = new Matrix(this.x,m.y);
  94                 for(int i = 0;i < o.x;i++) for(int j = 0;j < o.y;j++) {
  95                         for(int z = 0;z < this.y;z++)   o.matrix[i][j] += this.matrix[i][z] * m.matrix[z][j];
  96                 }
  97                 return o;
  98         }
  99
 100         /** Return matrix representing this matrix with swapped rows a and b */
 101         public Matrix swap_rows(int a, int b) {
 102                 Matrix o = new Matrix(x,y);
 103                 int i, j;
 104                 for(i = 0;i < o.x;i++) for(j = 0;j < o.y;j++) o.matrix[i][j] += this.matrix[i][j];
 105                 float tmp[] = o.matrix[a];
 106                 o.matrix[a] = o.matrix[b];
 107                 o.matrix[b] = tmp;
 108                 return o;
 109         }
 110
 111         /** Return determinant of this matrix */
 112         public double determinant() {
 113                 System.err.println("TODO: Determinant!");
 114                 return 0;
 115         }
 116
 117         /*public float SIM_MIN(float a, float b) {
 118         return (a < b ? a : b);
 119         }
 120
 121         public double fabs(double a) {
 122         return Math.abs(a);
 123         }*/
 124
 125         /** Return matrix representing upper triangle format of this matrix */
 126         public Matrix echelon() {
 127                 System.err.println("Reducing to echelon row form is not working properly!");
 128                 //return null;
 129                 Matrix o = new Matrix(x,y);
 130                 int i, j;
 131                 for(i = 0;i < o.x;i++) for(j = 0;j < o.y;j++) o.matrix[i][j] += this.matrix[i][j];
 132
 133                 for(int row = x; row >= 0; row--) {
 134                         //reduceRow(row);
 135         double multiplier;
 136         for(j=row+1; j < y; j++) {
 137                 if(o.matrix[row][j] != 0) {
 138                 multiplier = -o.matrix[row][j];
 139                 //addRow(j, row, multiplier);
 140                                                         //(int fromRow, int toRow, double mult)
 141                                                                 for(i=0; i<y; i++) {
 142                                                 o.matrix[row][i] += o.matrix[j][i]*multiplier;
 143                                         }
 144                 }
 145         }
 146     }
 147                 /*int lead = 0;
 148
 149                 for(int r = 0; r < x; r++) {
 150                         if(x <= lead)   {
 151                                 return o;
 152                         }
 153                         i = r;
 154                         while(o.matrix[i][lead] == 0) {
 155                                 i++;
 156                                 if(x == i) {
 157                                         i = r;
 158                                         lead++;
 159                                         if(y == lead)   {
 160                                                 return o;
 161                                         }
 162                                 }
 163                         }
 164                         o = o.swap_rows(i, r);
 165                         for(j = 0;j < y; j++) o.matrix[r][j] /= o.matrix[r][lead];
 166                         for(int row = 0; row < x; row++)
 167                         {
 168                                 if(row != r)
 169                                 {
 170                                         for(int l = 0; l < y; l++)
 171                                                  o.matrix[row][l] -= o.matrix[i][lead] * o.matrix[r][l];
 172                                 }
 173                         }
 174                         lead++;
 175                 }
 176                 */
 177
 178                 return o;
 179         }
 180
 181         /** Serialize this object to file specified by its name (and path) */
 182         public boolean save(String file) {
 183                 try {
 184         ObjectOutputStream os = new ObjectOutputStream(new FileOutputStream(file));
 185         os.writeObject(this);
 186         os.close();
 187                 } catch (Exception e) {
 188       e.printStackTrace();
 189                         return false;
 190                 }
 191                 return true;
 192         }
 193
 194         /** Deserialize and return Matrix object from file specified by its name (and path) */
 195         public static Matrix load(String file) {
 196                 Matrix m = null;
 197                 try {
 198         ObjectInputStream is = new ObjectInputStream(new FileInputStream(file));
 199         m = (Matrix) is.readObject();
 200         is.close();
 201                 } catch (Exception e) {
 202       e.printStackTrace();
 203                 }
 204                 return m;
 205         }
 206
 207
 208 }
 209
 210 /** Class demonstrating usage of Matrix class */
 211 public class matice {
 212         public static void main(String[] argv) {
 213                 System.out.println("You has matrix! Follow the black habit ;o)\n");
 214
 215                 String file = "f.matrix";
 216
 217                 System.out.println("Created matrix F and saved to file "+file+" =");
 218                 Matrix f = new Matrix(3,3); f.randomize(2); f.print();
 219                 f.save(file);
 220
 221                 System.out.println("Loaded matrix G from file "+file+" =");
 222                 Matrix g = Matrix.load(file); g.print();
 223
 224                 System.exit(0);
 225
 226                 System.out.println("Created matrix A =");
 227                 Matrix a = new Matrix(3,3); a.randomize(2); a.print();
 228
 229                 System.out.println("Created matrix B =");
 230                 Matrix b = new Matrix(new float[][] {
 231       {1, 2, 3},
 232       {4, 5, 6},
 233       {7, 8, 9}
 234     });
 235                 b.print();
 236
 237                 /*System.out.println("Row Echelon form of B =");
 238                 b.echelon().print();
 239                 */
 240
 241                 System.out.println("A + B =");
 242                 a.add(b).print();
 243
 244                 System.out.println("A - B =");
 245                 a.subtract(b).print();
 246
 247                 System.out.println("A * B =");
 248                 a.multiply(b).print();
 249
 250                 System.out.println("Swap rows 0 and 1 of matrix B =");
 251                 b.swap_rows(0,1).print();
 252
 253                 System.out.println("Created matrix C =");
 254                 Matrix c = new Matrix(3,4); c.randomize(20); c.print();
 255
 256                 System.out.println("Created matrix D =");
 257                 Matrix d = new Matrix(4,2); d.randomize(10); d.print();
 258
 259                 System.out.println("C . D =");
 260                 c.mmultiply(d).print();
 261         }
 262 }
 263
 264 /* Echelon debug:
 265
 266 B: matrix(
 267  [1,2,3],
 268  [4,5,6],
 269  [7,8,9]
 270 );
 271
 272 echelon(B) = matrix(
 273 [1,2,3],
 274 [0,1,2],
 275 [0,0,0]
 276 )
 277
 278 **********************************/
 279
 280
 281 /* Example:
 282
 283 0 ;) harvie@harvie-ntb prg $ javac matice.java; java matice
 284 You has matrix! Follow the black habit ;o)
 285
 286 Created matrix A =
 287 |       0       0       0       |
 288 |       0       0       1       |
 289 |       1       1       0       |
 290
 291 Created matrix B =
 292 |       8       9       8       |
 293 |       7       9       6       |
 294 |       7       4       8       |
 295
 296 A + B =
 297 |       8       9       8       |
 298 |       7       9       7       |
 299 |       8       5       8       |
 300
 301 A - B =
 302 |       -8      -9      -8      |
 303 |       -7      -9      -5      |
 304 |       -6      -3      -8      |
 305
 306 A * B =
 307 |       0       0       0       |
 308 |       0       0       6       |
 309 |       7       4       0       |
 310
 311 Created matrix C =
 312 |       19      12      2       7       |
 313 |       1       3       8       12      |
 314 |       7       5       13      4       |
 315
 316 Created matrix D =
 317 |       8       2       |
 318 |       7       8       |
 319 |       8       4       |
 320 |       5       7       |
 321
 322 C . D =
 323 |       287     191     |
 324 |       153     142     |
 325 |       215     134     |
 326
 327 */