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[mirrors/Programs.git] / java / matice.java.txt
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 */
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