1
|
|
|
<?php |
2
|
|
|
|
3
|
|
|
namespace PhpOffice\PhpSpreadsheet\Shared\JAMA; |
4
|
|
|
|
5
|
|
|
/** |
6
|
|
|
* For an m-by-n matrix A with m >= n, the singular value decomposition is |
7
|
|
|
* an m-by-n orthogonal matrix U, an n-by-n diagonal matrix S, and |
8
|
|
|
* an n-by-n orthogonal matrix V so that A = U*S*V'. |
9
|
|
|
* |
10
|
|
|
* The singular values, sigma[$k] = S[$k][$k], are ordered so that |
11
|
|
|
* sigma[0] >= sigma[1] >= ... >= sigma[n-1]. |
12
|
|
|
* |
13
|
|
|
* The singular value decompostion always exists, so the constructor will |
14
|
|
|
* never fail. The matrix condition number and the effective numerical |
15
|
|
|
* rank can be computed from this decomposition. |
16
|
|
|
* |
17
|
|
|
* @author Paul Meagher |
18
|
|
|
* |
19
|
|
|
* @version 1.1 |
20
|
|
|
*/ |
21
|
|
|
class SingularValueDecomposition |
22
|
|
|
{ |
23
|
|
|
/** |
24
|
|
|
* Internal storage of U. |
25
|
|
|
* |
26
|
|
|
* @var array |
27
|
|
|
*/ |
28
|
|
|
private $U = []; |
29
|
|
|
|
30
|
|
|
/** |
31
|
|
|
* Internal storage of V. |
32
|
|
|
* |
33
|
|
|
* @var array |
34
|
|
|
*/ |
35
|
|
|
private $V = []; |
36
|
|
|
|
37
|
|
|
/** |
38
|
|
|
* Internal storage of singular values. |
39
|
|
|
* |
40
|
|
|
* @var array |
41
|
|
|
*/ |
42
|
|
|
private $s = []; |
43
|
|
|
|
44
|
|
|
/** |
45
|
|
|
* Row dimension. |
46
|
|
|
* |
47
|
|
|
* @var int |
48
|
|
|
*/ |
49
|
|
|
private $m; |
50
|
|
|
|
51
|
|
|
/** |
52
|
|
|
* Column dimension. |
53
|
|
|
* |
54
|
|
|
* @var int |
55
|
|
|
*/ |
56
|
|
|
private $n; |
57
|
|
|
|
58
|
|
|
/** |
59
|
|
|
* Construct the singular value decomposition. |
60
|
|
|
* |
61
|
|
|
* Derived from LINPACK code. |
62
|
|
|
* |
63
|
|
|
* @param mixed $Arg Rectangular matrix |
64
|
|
|
*/ |
65
|
|
|
public function __construct($Arg) |
66
|
|
|
{ |
67
|
|
|
// Initialize. |
68
|
|
|
$A = $Arg->getArrayCopy(); |
69
|
|
|
$this->m = $Arg->getRowDimension(); |
70
|
|
|
$this->n = $Arg->getColumnDimension(); |
71
|
|
|
$nu = min($this->m, $this->n); |
72
|
|
|
$e = []; |
73
|
|
|
$work = []; |
74
|
|
|
$wantu = true; |
75
|
|
|
$wantv = true; |
76
|
|
|
$nct = min($this->m - 1, $this->n); |
77
|
|
|
$nrt = max(0, min($this->n - 2, $this->m)); |
78
|
|
|
|
79
|
|
|
// Reduce A to bidiagonal form, storing the diagonal elements |
80
|
|
|
// in s and the super-diagonal elements in e. |
81
|
|
|
$kMax = max($nct, $nrt); |
82
|
|
|
for ($k = 0; $k < $kMax; ++$k) { |
83
|
|
|
if ($k < $nct) { |
84
|
|
|
// Compute the transformation for the k-th column and |
85
|
|
|
// place the k-th diagonal in s[$k]. |
86
|
|
|
// Compute 2-norm of k-th column without under/overflow. |
87
|
|
|
$this->s[$k] = 0; |
88
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
89
|
|
|
$this->s[$k] = hypo($this->s[$k], $A[$i][$k]); |
90
|
|
|
} |
91
|
|
|
if ($this->s[$k] != 0.0) { |
92
|
|
|
if ($A[$k][$k] < 0.0) { |
93
|
|
|
$this->s[$k] = -$this->s[$k]; |
94
|
|
|
} |
95
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
96
|
|
|
$A[$i][$k] /= $this->s[$k]; |
97
|
|
|
} |
98
|
|
|
$A[$k][$k] += 1.0; |
99
|
|
|
} |
100
|
|
|
$this->s[$k] = -$this->s[$k]; |
101
|
|
|
} |
102
|
|
|
|
103
|
|
|
for ($j = $k + 1; $j < $this->n; ++$j) { |
104
|
|
|
if (($k < $nct) & ($this->s[$k] != 0.0)) { |
|
|
|
|
105
|
|
|
// Apply the transformation. |
106
|
|
|
$t = 0; |
107
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
108
|
|
|
$t += $A[$i][$k] * $A[$i][$j]; |
109
|
|
|
} |
110
|
|
|
$t = -$t / $A[$k][$k]; |
111
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
112
|
|
|
$A[$i][$j] += $t * $A[$i][$k]; |
113
|
|
|
} |
114
|
|
|
// Place the k-th row of A into e for the |
115
|
|
|
// subsequent calculation of the row transformation. |
116
|
|
|
$e[$j] = $A[$k][$j]; |
117
|
|
|
} |
118
|
|
|
} |
119
|
|
|
|
120
|
|
|
if ($wantu and ($k < $nct)) { |
121
|
|
|
// Place the transformation in U for subsequent back |
122
|
|
|
// multiplication. |
123
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
124
|
|
|
$this->U[$i][$k] = $A[$i][$k]; |
125
|
|
|
} |
126
|
|
|
} |
127
|
|
|
|
128
|
|
|
if ($k < $nrt) { |
129
|
|
|
// Compute the k-th row transformation and place the |
130
|
|
|
// k-th super-diagonal in e[$k]. |
131
|
|
|
// Compute 2-norm without under/overflow. |
132
|
|
|
$e[$k] = 0; |
133
|
|
|
for ($i = $k + 1; $i < $this->n; ++$i) { |
134
|
|
|
$e[$k] = hypo($e[$k], $e[$i]); |
135
|
|
|
} |
136
|
|
|
if ($e[$k] != 0.0) { |
137
|
|
|
if ($e[$k + 1] < 0.0) { |
138
|
|
|
$e[$k] = -$e[$k]; |
139
|
|
|
} |
140
|
|
|
for ($i = $k + 1; $i < $this->n; ++$i) { |
141
|
|
|
$e[$i] /= $e[$k]; |
142
|
|
|
} |
143
|
|
|
$e[$k + 1] += 1.0; |
144
|
|
|
} |
145
|
|
|
$e[$k] = -$e[$k]; |
146
|
|
|
if (($k + 1 < $this->m) and ($e[$k] != 0.0)) { |
147
|
|
|
// Apply the transformation. |
148
|
|
|
for ($i = $k + 1; $i < $this->m; ++$i) { |
149
|
|
|
$work[$i] = 0.0; |
150
|
|
|
} |
151
|
|
|
for ($j = $k + 1; $j < $this->n; ++$j) { |
152
|
|
|
for ($i = $k + 1; $i < $this->m; ++$i) { |
153
|
|
|
$work[$i] += $e[$j] * $A[$i][$j]; |
154
|
|
|
} |
155
|
|
|
} |
156
|
|
|
for ($j = $k + 1; $j < $this->n; ++$j) { |
157
|
|
|
$t = -$e[$j] / $e[$k + 1]; |
158
|
|
|
for ($i = $k + 1; $i < $this->m; ++$i) { |
159
|
|
|
$A[$i][$j] += $t * $work[$i]; |
160
|
|
|
} |
161
|
|
|
} |
162
|
|
|
} |
163
|
|
|
if ($wantv) { |
164
|
|
|
// Place the transformation in V for subsequent |
165
|
|
|
// back multiplication. |
166
|
|
|
for ($i = $k + 1; $i < $this->n; ++$i) { |
167
|
|
|
$this->V[$i][$k] = $e[$i]; |
168
|
|
|
} |
169
|
|
|
} |
170
|
|
|
} |
171
|
|
|
} |
172
|
|
|
|
173
|
|
|
// Set up the final bidiagonal matrix or order p. |
174
|
|
|
$p = min($this->n, $this->m + 1); |
175
|
|
|
if ($nct < $this->n) { |
176
|
|
|
$this->s[$nct] = $A[$nct][$nct]; |
177
|
|
|
} |
178
|
|
|
if ($this->m < $p) { |
179
|
|
|
$this->s[$p - 1] = 0.0; |
180
|
|
|
} |
181
|
|
|
if ($nrt + 1 < $p) { |
182
|
|
|
$e[$nrt] = $A[$nrt][$p - 1]; |
183
|
|
|
} |
184
|
|
|
$e[$p - 1] = 0.0; |
185
|
|
|
// If required, generate U. |
186
|
|
|
if ($wantu) { |
187
|
|
|
for ($j = $nct; $j < $nu; ++$j) { |
188
|
|
|
for ($i = 0; $i < $this->m; ++$i) { |
189
|
|
|
$this->U[$i][$j] = 0.0; |
190
|
|
|
} |
191
|
|
|
$this->U[$j][$j] = 1.0; |
192
|
|
|
} |
193
|
|
|
for ($k = $nct - 1; $k >= 0; --$k) { |
194
|
|
|
if ($this->s[$k] != 0.0) { |
195
|
|
|
for ($j = $k + 1; $j < $nu; ++$j) { |
196
|
|
|
$t = 0; |
197
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
198
|
|
|
$t += $this->U[$i][$k] * $this->U[$i][$j]; |
199
|
|
|
} |
200
|
|
|
$t = -$t / $this->U[$k][$k]; |
201
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
202
|
|
|
$this->U[$i][$j] += $t * $this->U[$i][$k]; |
203
|
|
|
} |
204
|
|
|
} |
205
|
|
|
for ($i = $k; $i < $this->m; ++$i) { |
206
|
|
|
$this->U[$i][$k] = -$this->U[$i][$k]; |
207
|
|
|
} |
208
|
|
|
$this->U[$k][$k] = 1.0 + $this->U[$k][$k]; |
209
|
|
|
for ($i = 0; $i < $k - 1; ++$i) { |
210
|
|
|
$this->U[$i][$k] = 0.0; |
211
|
|
|
} |
212
|
|
|
} else { |
213
|
|
|
for ($i = 0; $i < $this->m; ++$i) { |
214
|
|
|
$this->U[$i][$k] = 0.0; |
215
|
|
|
} |
216
|
|
|
$this->U[$k][$k] = 1.0; |
217
|
|
|
} |
218
|
|
|
} |
219
|
|
|
} |
220
|
|
|
|
221
|
|
|
// If required, generate V. |
222
|
|
|
if ($wantv) { |
223
|
|
|
for ($k = $this->n - 1; $k >= 0; --$k) { |
224
|
|
|
if (($k < $nrt) and ($e[$k] != 0.0)) { |
225
|
|
|
for ($j = $k + 1; $j < $nu; ++$j) { |
226
|
|
|
$t = 0; |
227
|
|
|
for ($i = $k + 1; $i < $this->n; ++$i) { |
228
|
|
|
$t += $this->V[$i][$k] * $this->V[$i][$j]; |
229
|
|
|
} |
230
|
|
|
$t = -$t / $this->V[$k + 1][$k]; |
231
|
|
|
for ($i = $k + 1; $i < $this->n; ++$i) { |
232
|
|
|
$this->V[$i][$j] += $t * $this->V[$i][$k]; |
233
|
|
|
} |
234
|
|
|
} |
235
|
|
|
} |
236
|
|
|
for ($i = 0; $i < $this->n; ++$i) { |
237
|
|
|
$this->V[$i][$k] = 0.0; |
238
|
|
|
} |
239
|
|
|
$this->V[$k][$k] = 1.0; |
240
|
|
|
} |
241
|
|
|
} |
242
|
|
|
|
243
|
|
|
// Main iteration loop for the singular values. |
244
|
|
|
$pp = $p - 1; |
245
|
|
|
$iter = 0; |
246
|
|
|
$eps = pow(2.0, -52.0); |
247
|
|
|
|
248
|
|
|
while ($p > 0) { |
249
|
|
|
// Here is where a test for too many iterations would go. |
250
|
|
|
// This section of the program inspects for negligible |
251
|
|
|
// elements in the s and e arrays. On completion the |
252
|
|
|
// variables kase and k are set as follows: |
253
|
|
|
// kase = 1 if s(p) and e[k-1] are negligible and k<p |
254
|
|
|
// kase = 2 if s(k) is negligible and k<p |
255
|
|
|
// kase = 3 if e[k-1] is negligible, k<p, and |
256
|
|
|
// s(k), ..., s(p) are not negligible (qr step). |
257
|
|
|
// kase = 4 if e(p-1) is negligible (convergence). |
258
|
|
|
for ($k = $p - 2; $k >= -1; --$k) { |
259
|
|
|
if ($k == -1) { |
260
|
|
|
break; |
261
|
|
|
} |
262
|
|
|
if (abs($e[$k]) <= $eps * (abs($this->s[$k]) + abs($this->s[$k + 1]))) { |
263
|
|
|
$e[$k] = 0.0; |
264
|
|
|
|
265
|
|
|
break; |
266
|
|
|
} |
267
|
|
|
} |
268
|
|
|
if ($k == $p - 2) { |
269
|
|
|
$kase = 4; |
270
|
|
|
} else { |
271
|
|
|
for ($ks = $p - 1; $ks >= $k; --$ks) { |
272
|
|
|
if ($ks == $k) { |
273
|
|
|
break; |
274
|
|
|
} |
275
|
|
|
$t = ($ks != $p ? abs($e[$ks]) : 0.) + ($ks != $k + 1 ? abs($e[$ks - 1]) : 0.); |
276
|
|
|
if (abs($this->s[$ks]) <= $eps * $t) { |
277
|
|
|
$this->s[$ks] = 0.0; |
278
|
|
|
|
279
|
|
|
break; |
280
|
|
|
} |
281
|
|
|
} |
282
|
|
|
if ($ks == $k) { |
283
|
|
|
$kase = 3; |
284
|
|
|
} elseif ($ks == $p - 1) { |
285
|
|
|
$kase = 1; |
286
|
|
|
} else { |
287
|
|
|
$kase = 2; |
288
|
|
|
$k = $ks; |
289
|
|
|
} |
290
|
|
|
} |
291
|
|
|
++$k; |
292
|
|
|
|
293
|
|
|
// Perform the task indicated by kase. |
294
|
|
|
switch ($kase) { |
295
|
|
|
// Deflate negligible s(p). |
296
|
|
|
case 1: |
297
|
|
|
$f = $e[$p - 2]; |
298
|
|
|
$e[$p - 2] = 0.0; |
299
|
|
|
for ($j = $p - 2; $j >= $k; --$j) { |
300
|
|
|
$t = hypo($this->s[$j], $f); |
301
|
|
|
$cs = $this->s[$j] / $t; |
302
|
|
|
$sn = $f / $t; |
303
|
|
|
$this->s[$j] = $t; |
304
|
|
|
if ($j != $k) { |
305
|
|
|
$f = -$sn * $e[$j - 1]; |
306
|
|
|
$e[$j - 1] = $cs * $e[$j - 1]; |
307
|
|
|
} |
308
|
|
|
if ($wantv) { |
309
|
|
|
for ($i = 0; $i < $this->n; ++$i) { |
310
|
|
|
$t = $cs * $this->V[$i][$j] + $sn * $this->V[$i][$p - 1]; |
311
|
|
|
$this->V[$i][$p - 1] = -$sn * $this->V[$i][$j] + $cs * $this->V[$i][$p - 1]; |
312
|
|
|
$this->V[$i][$j] = $t; |
313
|
|
|
} |
314
|
|
|
} |
315
|
|
|
} |
316
|
|
|
|
317
|
|
|
break; |
318
|
|
|
// Split at negligible s(k). |
319
|
|
|
case 2: |
320
|
|
|
$f = $e[$k - 1]; |
321
|
|
|
$e[$k - 1] = 0.0; |
322
|
|
|
for ($j = $k; $j < $p; ++$j) { |
323
|
|
|
$t = hypo($this->s[$j], $f); |
324
|
|
|
$cs = $this->s[$j] / $t; |
325
|
|
|
$sn = $f / $t; |
326
|
|
|
$this->s[$j] = $t; |
327
|
|
|
$f = -$sn * $e[$j]; |
328
|
|
|
$e[$j] = $cs * $e[$j]; |
329
|
|
|
if ($wantu) { |
330
|
|
|
for ($i = 0; $i < $this->m; ++$i) { |
331
|
|
|
$t = $cs * $this->U[$i][$j] + $sn * $this->U[$i][$k - 1]; |
332
|
|
|
$this->U[$i][$k - 1] = -$sn * $this->U[$i][$j] + $cs * $this->U[$i][$k - 1]; |
333
|
|
|
$this->U[$i][$j] = $t; |
334
|
|
|
} |
335
|
|
|
} |
336
|
|
|
} |
337
|
|
|
|
338
|
|
|
break; |
339
|
|
|
// Perform one qr step. |
340
|
|
|
case 3: |
341
|
|
|
// Calculate the shift. |
342
|
|
|
$scale = max(max(max(max(abs($this->s[$p - 1]), abs($this->s[$p - 2])), abs($e[$p - 2])), abs($this->s[$k])), abs($e[$k])); |
343
|
|
|
$sp = $this->s[$p - 1] / $scale; |
344
|
|
|
$spm1 = $this->s[$p - 2] / $scale; |
345
|
|
|
$epm1 = $e[$p - 2] / $scale; |
346
|
|
|
$sk = $this->s[$k] / $scale; |
347
|
|
|
$ek = $e[$k] / $scale; |
348
|
|
|
$b = (($spm1 + $sp) * ($spm1 - $sp) + $epm1 * $epm1) / 2.0; |
349
|
|
|
$c = ($sp * $epm1) * ($sp * $epm1); |
350
|
|
|
$shift = 0.0; |
351
|
|
|
if (($b != 0.0) || ($c != 0.0)) { |
352
|
|
|
$shift = sqrt($b * $b + $c); |
353
|
|
|
if ($b < 0.0) { |
354
|
|
|
$shift = -$shift; |
355
|
|
|
} |
356
|
|
|
$shift = $c / ($b + $shift); |
357
|
|
|
} |
358
|
|
|
$f = ($sk + $sp) * ($sk - $sp) + $shift; |
359
|
|
|
$g = $sk * $ek; |
360
|
|
|
// Chase zeros. |
361
|
|
|
for ($j = $k; $j < $p - 1; ++$j) { |
362
|
|
|
$t = hypo($f, $g); |
363
|
|
|
$cs = $f / $t; |
364
|
|
|
$sn = $g / $t; |
365
|
|
|
if ($j != $k) { |
366
|
|
|
$e[$j - 1] = $t; |
367
|
|
|
} |
368
|
|
|
$f = $cs * $this->s[$j] + $sn * $e[$j]; |
369
|
|
|
$e[$j] = $cs * $e[$j] - $sn * $this->s[$j]; |
370
|
|
|
$g = $sn * $this->s[$j + 1]; |
371
|
|
|
$this->s[$j + 1] = $cs * $this->s[$j + 1]; |
372
|
|
|
if ($wantv) { |
373
|
|
|
for ($i = 0; $i < $this->n; ++$i) { |
374
|
|
|
$t = $cs * $this->V[$i][$j] + $sn * $this->V[$i][$j + 1]; |
375
|
|
|
$this->V[$i][$j + 1] = -$sn * $this->V[$i][$j] + $cs * $this->V[$i][$j + 1]; |
376
|
|
|
$this->V[$i][$j] = $t; |
377
|
|
|
} |
378
|
|
|
} |
379
|
|
|
$t = hypo($f, $g); |
380
|
|
|
$cs = $f / $t; |
381
|
|
|
$sn = $g / $t; |
382
|
|
|
$this->s[$j] = $t; |
383
|
|
|
$f = $cs * $e[$j] + $sn * $this->s[$j + 1]; |
384
|
|
|
$this->s[$j + 1] = -$sn * $e[$j] + $cs * $this->s[$j + 1]; |
385
|
|
|
$g = $sn * $e[$j + 1]; |
386
|
|
|
$e[$j + 1] = $cs * $e[$j + 1]; |
387
|
|
|
if ($wantu && ($j < $this->m - 1)) { |
388
|
|
|
for ($i = 0; $i < $this->m; ++$i) { |
389
|
|
|
$t = $cs * $this->U[$i][$j] + $sn * $this->U[$i][$j + 1]; |
390
|
|
|
$this->U[$i][$j + 1] = -$sn * $this->U[$i][$j] + $cs * $this->U[$i][$j + 1]; |
391
|
|
|
$this->U[$i][$j] = $t; |
392
|
|
|
} |
393
|
|
|
} |
394
|
|
|
} |
395
|
|
|
$e[$p - 2] = $f; |
396
|
|
|
$iter = $iter + 1; |
397
|
|
|
|
398
|
|
|
break; |
399
|
|
|
// Convergence. |
400
|
|
|
case 4: |
401
|
|
|
// Make the singular values positive. |
402
|
|
|
if ($this->s[$k] <= 0.0) { |
403
|
|
|
$this->s[$k] = ($this->s[$k] < 0.0 ? -$this->s[$k] : 0.0); |
404
|
|
|
if ($wantv) { |
405
|
|
|
for ($i = 0; $i <= $pp; ++$i) { |
406
|
|
|
$this->V[$i][$k] = -$this->V[$i][$k]; |
407
|
|
|
} |
408
|
|
|
} |
409
|
|
|
} |
410
|
|
|
// Order the singular values. |
411
|
|
|
while ($k < $pp) { |
412
|
|
|
if ($this->s[$k] >= $this->s[$k + 1]) { |
413
|
|
|
break; |
414
|
|
|
} |
415
|
|
|
$t = $this->s[$k]; |
416
|
|
|
$this->s[$k] = $this->s[$k + 1]; |
417
|
|
|
$this->s[$k + 1] = $t; |
418
|
|
|
if ($wantv and ($k < $this->n - 1)) { |
419
|
|
|
for ($i = 0; $i < $this->n; ++$i) { |
420
|
|
|
$t = $this->V[$i][$k + 1]; |
421
|
|
|
$this->V[$i][$k + 1] = $this->V[$i][$k]; |
422
|
|
|
$this->V[$i][$k] = $t; |
423
|
|
|
} |
424
|
|
|
} |
425
|
|
|
if ($wantu and ($k < $this->m - 1)) { |
426
|
|
|
for ($i = 0; $i < $this->m; ++$i) { |
427
|
|
|
$t = $this->U[$i][$k + 1]; |
428
|
|
|
$this->U[$i][$k + 1] = $this->U[$i][$k]; |
429
|
|
|
$this->U[$i][$k] = $t; |
430
|
|
|
} |
431
|
|
|
} |
432
|
|
|
++$k; |
433
|
|
|
} |
434
|
|
|
$iter = 0; |
435
|
|
|
--$p; |
436
|
|
|
|
437
|
|
|
break; |
438
|
|
|
} // end switch |
439
|
|
|
} // end while |
440
|
|
|
} |
441
|
|
|
|
442
|
|
|
/** |
443
|
|
|
* Return the left singular vectors. |
444
|
|
|
* |
445
|
|
|
* @return Matrix U |
446
|
|
|
*/ |
447
|
|
|
public function getU() |
448
|
|
|
{ |
449
|
|
|
return new Matrix($this->U, $this->m, min($this->m + 1, $this->n)); |
450
|
|
|
} |
451
|
|
|
|
452
|
|
|
/** |
453
|
|
|
* Return the right singular vectors. |
454
|
|
|
* |
455
|
|
|
* @return Matrix V |
456
|
|
|
*/ |
457
|
|
|
public function getV() |
458
|
|
|
{ |
459
|
|
|
return new Matrix($this->V); |
460
|
|
|
} |
461
|
|
|
|
462
|
|
|
/** |
463
|
|
|
* Return the one-dimensional array of singular values. |
464
|
|
|
* |
465
|
|
|
* @return array diagonal of S |
466
|
|
|
*/ |
467
|
|
|
public function getSingularValues() |
468
|
|
|
{ |
469
|
|
|
return $this->s; |
470
|
|
|
} |
471
|
|
|
|
472
|
|
|
/** |
473
|
|
|
* Return the diagonal matrix of singular values. |
474
|
|
|
* |
475
|
|
|
* @return Matrix S |
476
|
|
|
*/ |
477
|
|
|
public function getS() |
478
|
|
|
{ |
479
|
|
|
for ($i = 0; $i < $this->n; ++$i) { |
480
|
|
|
for ($j = 0; $j < $this->n; ++$j) { |
481
|
|
|
$S[$i][$j] = 0.0; |
482
|
|
|
} |
483
|
|
|
$S[$i][$i] = $this->s[$i]; |
484
|
|
|
} |
485
|
|
|
|
486
|
|
|
return new Matrix($S); |
|
|
|
|
487
|
|
|
} |
488
|
|
|
|
489
|
|
|
/** |
490
|
|
|
* Two norm. |
491
|
|
|
* |
492
|
|
|
* @return float max(S) |
493
|
|
|
*/ |
494
|
|
|
public function norm2() |
495
|
|
|
{ |
496
|
|
|
return $this->s[0]; |
497
|
|
|
} |
498
|
|
|
|
499
|
|
|
/** |
500
|
|
|
* Two norm condition number. |
501
|
|
|
* |
502
|
|
|
* @return float max(S)/min(S) |
503
|
|
|
*/ |
504
|
|
|
public function cond() |
505
|
|
|
{ |
506
|
|
|
return $this->s[0] / $this->s[min($this->m, $this->n) - 1]; |
507
|
|
|
} |
508
|
|
|
|
509
|
|
|
/** |
510
|
|
|
* Effective numerical matrix rank. |
511
|
|
|
* |
512
|
|
|
* @return int Number of nonnegligible singular values |
513
|
|
|
*/ |
514
|
|
|
public function rank() |
515
|
|
|
{ |
516
|
|
|
$eps = pow(2.0, -52.0); |
517
|
|
|
$tol = max($this->m, $this->n) * $this->s[0] * $eps; |
518
|
|
|
$r = 0; |
519
|
|
|
$iMax = count($this->s); |
520
|
|
|
for ($i = 0; $i < $iMax; ++$i) { |
521
|
|
|
if ($this->s[$i] > $tol) { |
522
|
|
|
++$r; |
523
|
|
|
} |
524
|
|
|
} |
525
|
|
|
|
526
|
|
|
return $r; |
527
|
|
|
} |
528
|
|
|
} |
529
|
|
|
|