-
Notifications
You must be signed in to change notification settings - Fork 2
/
MbEigensystem.cpp
1345 lines (1225 loc) · 30.4 KB
/
MbEigensystem.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*!
* \file
* This file contains the functions in the MbEigensystem class, which
* calculates and stores the eigensystem of a square real matrix.
*
* \brief Function definitions for MbEigensystem
*
* MrBayes version 4.0 beta
*
* (c) Copyright 2005.
* \version 4.0 Beta
* \date Last modified: $Date: 2006/06/04 16:25:45 $
* \author John Huelsenbeck (1)
* \author Bret Larget (2)
* \author Paul van der Mark (3)
* \author Fredrik Ronquist (3)
* \author Donald Simon (4)
* \author (authors listed in alphabetical order)
* (1) Division of Biological Science, University of California, San Diego
* (2) Departments of Botany and of Statistics, University of Wisconsin - Madison
* (3) School of Computational Science, Florida State University
* (4) Department of Mathematics/Computer Science, Duquesne University
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License (the file gpl.txt included with this
* distribution or http: *www.gnu.org/licenses/gpl.txt) for more
* details.
*
* $Id: MbEigensystem.C,v 1.1 2006/06/04 16:25:45 ronquist Exp $
*/
#include "MbEigensystem.h"
#include <cmath>
//#include <limits>
using namespace std;
/*!
* The constructor allocates space for the eigensystem, calculates it from
* the input matrix, and then stores it so that the components can be
* retrieved when needed. This constructor returns an empty Eigensystem
* if the input matrix is not square.
*
* \brief Constructor
* \param m Matrix for which the eigensystem should be calculated
*/
MbEigensystem::MbEigensystem(const MbMatrix<double> &m)
: n(0), isComplex(false) {
// check that the matrix, m, is square and return
// an empty eigensystem if it is not
if ( m.dim1() != m.dim2() ) {
return;
}
// set the dimensions of the matrix
n = m.dim2();
// allocate and initialize components of eigensystem
// assuming it is going to be real and not complex
eigenvectors = MbMatrix<double>(n, n, 0.0);
inverseEigenvectors = MbMatrix<double>(n, n, 0.0);
realEigenvalues = MbVector<double>(n, 0.0);
imaginaryEigenvalues = MbVector<double>(n, 0.0);
// calculate eigenvalues and eigenvectors for a real matrix
update (m);
}
/*!
* Destructor. It checks whether the current eigensystem is
* complex and acts accordingly.
*
* \brief Destructor
*/
MbEigensystem::~MbEigensystem(void) {
}
/*!
* Allocate space for complex eigenvectors
*
* \brief Allocate complex eigenvectors
*/
void MbEigensystem::allocateComplexEigenvectors(void) {
/* allocate the complex eigenvector and inverse eigenvector matrices */
complexEigenvectors = MbMatrix<mbcompl>(n,n);
complexInverseEigenvectors = MbMatrix<mbcompl>(n,n);
}
/*!
* This function balances the matrix A so that the rows with zero entries
* off the diagonal are isolated and the remaining columns and rows are
* resized to have one norm close to 1.0.
*
* \brief Balance matrix A
* \param a [in/out] Real n X n matrix [in] Scaled matrix [out]
* \param low [out] First relevant row index
* \param high [out] Last relevant row index
* \param scale [out] A vector containing the isolated eigenvalues in
* the positions 0 to low-1 and high to n-1. Its other components contain
* the scaling factors for transforming A
*/
void MbEigensystem::balance(MbMatrix<double> &a, MbVector<double> &scale, int *low, int *high) {
//! \todo The code below should be RADIX = numeric_limits<double>::radix;
// check why this does not work with vcpp (problem with <limits> or compile settings)
const double RADIX = 2;
double sqrdx = RADIX * RADIX;
int m = 0;
int k = n - 1;
bool continueLoop;
do
{
continueLoop = false;
for (int j=k; j>=0; j--)
{
double r = 0.0;
for (int i=0; i<=k; i++)
if ( i != j )
r += fabs(a[j][i]);
if ( r == 0.0 )
{
scale[k] = (double)j;
if ( j != k )
{
for (int i=0; i<=k; i++)
{
double tempD = a[i][j];
a[i][j] = a[i][k];
a[i][k] = tempD;
}
for (int i=m; i<n; i++)
{
double tempD = a[j][i];
a[j][i] = a[k][i];
a[k][i] = tempD;
}
}
k--;
continueLoop = true;
}
}
} while (continueLoop);
do
{
continueLoop = false;
for (int j=m; j<=k; j++)
{
double c = 0.0;
for (int i=m; i<=k; i++)
if (i != j)
c += fabs(a[i][j]);
if ( c == 0.0 )
{
scale[m] = (double)j;
if ( j != m )
{
for (int i=0; i<=k; i++)
{
double tempD = a[i][m];
a[i][j] = a[i][m];
a[i][m] = tempD;
}
for (int i=m; i<n; i++)
{
double tempD = a[j][i];
a[j][i] = a[m][i];
a[m][i] = tempD;
}
}
m++;
continueLoop = true;
}
}
} while (continueLoop);
*low = m;
*high = k;
for (int i=m; i<=k; i++)
scale[i] = 1.0;
do
{
continueLoop = false;
for (int i=m; i<=k; i++)
{
double r = 0.0;
double c = 0.0;
for (int j=m; j<=k; j++)
if (j !=i)
{
c += fabs(a[j][i]);
r += fabs(a[i][j]);
}
double g = r / RADIX;
double f = 1.0;
double s = c + r;
while ( c < g )
{
f *= RADIX;
c *= sqrdx;
}
g = r * RADIX;
while ( c >= g )
{
f /= RADIX;
c /= sqrdx;
}
if ( (c + r) / f < 0.95 * s )
{
g = 1.0 / f;
scale[i] *= f;
continueLoop = true;
for (int j=m; j<n; j++)
a[i][j] *= g;
for (int j=0; j<=k; j++)
a[j][i] *= f;
}
}
} while (continueLoop);
}
/*!
* This function reverses the balancing (performed by balance) for
* the eigenvectors.
*
* \brief Reverse balancing
* \param eivec [in/out] Matrix of balanced [in] or non-normalized [out] eigenvectors
* \param low [in] Index to first nonzero row
* \param high [in] Index to last nonzero row
* \param scale [in] Vector of scalers from balance
* \param eivec [out]Scaling data from balance
*/
void MbEigensystem::balback(int low, int high, MbVector<double> &scale, MbMatrix<double> &eivec) {
for (int i=low; i<=high; i++)
{
double s = scale[i];
for (int j=0; j<n; j++)
eivec[i][j] *= s;
}
for (int i=low-1; i>=0; i--)
{
int k = (int)scale[i];
if ( k != i )
for (int j=0; j<n; j++)
{
double tempD = eivec[i][j];
eivec[i][j] = eivec[k][j];
eivec[k][j] = tempD;
}
}
for (int i=high+1; i<n; i++)
{
int k = (int)scale[i];
if ( k != i )
for (int j=0; j<n; j++)
{
double tempD = eivec[i][j];
eivec[i][j] = eivec[k][j];
eivec[k][j] = tempD;
}
}
}
/*!
* Check if there are complex eigenvalues.
*
* \brief Check for complex eigenvalues
* \return true if eigenvalues are complex
*/
bool MbEigensystem::checkForComplexEigenvalues(void) {
bool areThereComplexEigens = false;
for (int i=0; i<n; i++)
{
if (imaginaryEigenvalues[i] != 0.0)
{
areThereComplexEigens = true;
break;
}
}
return areThereComplexEigens;
}
/*!
* Back substitute into complex LU-decomposed matrix.
*
* \brief Back substitution into complex LU-decomposed matrix
* \param a [in/out] The matrix
* \param indx [in] ??
* \param b [in] ??
* \todo Does this work ? See statementes that are commented out. The
* first one does not correspond to the statement above, nor does the
* statement above make much sense in the context.
*/
void MbEigensystem::complexLUBackSubstitution(MbMatrix<mbcompl> &a, int *indx, MbVector<mbcompl> &b) {
int ip, j, ii = -1;
mbcompl sum;
for (int i=0; i<n; i++)
{
ip = indx[i];
sum = b[ip];
b[ip] = b[i];
if ( ii >= 0 )
{
for (j = ii; j <= i - 1; j++)
sum -= a[i][j] * b[j];
// was originally sum = a[i][j] - b[j]; this must be wrong!!
//sum = ComplexSubtraction (sum, ComplexMultiplication (a[i][j], b[j]));
}
else if ( (sum.real() != 0.0) || (sum.imag() != 0.0) )
ii = i;
b[i] = sum;
}
for (int i=n-1; i>=0; i--)
{
sum = b[i];
for (j=i+1; j<n; j++)
{
sum -= a[i][j] * b[j];
//sum = ComplexSubtraction (sum, ComplexMultiplication (a[i][j], b[j]));
}
b[i] = sum / a[i][i];
//b[i] = ComplexDivision (sum, a[i][i]);
}
}
/*!
* Calculate the LU-decomposition of the matrix a. The matrix a is replaced.
*
* \brief Calculate LU-decomposition
* \param a [in/out] The complex matrix [in], LU decomposition [out]
* \param vv [out] ??
* \param indx [out] ??
* \param pd [in/out] 1.0 or -1.0 on output if not NULL on input
* \return 0 if success, 1 if a is singular (has a row with all zeros)
*/
int MbEigensystem::complexLUDecompose(MbMatrix<mbcompl> &a, double *vv, int *indx, double *pd) {
double d = 1.0;
int imax = 0;
for (int i=0; i<n; i++)
{
double big = 0.0;
for (int j=0; j<n; j++)
{
double temp;
if ((temp = abs(a[i][j])) > big)
big = temp;
}
if ( big == 0.0 )
return (1);
vv[i] = 1.0 / big;
}
for (int j=0; j<n; j++)
{
for (int i=0; i<j; i++)
{
complex<double>sum = a[i][j];
for (int k=0; k<i; k++)
{
complex<double> x = a[i][k] * a[k][j];
sum -= x;
}
a[i][j] = sum;
}
double big = 0.0;
for (int i = j; i < n; i++)
{
complex<double> sum = a[i][j];
for (int k=0; k<j; k++)
{
complex<double> x = a[i][k] * a[k][j];
sum -= x;
}
a[i][j] = sum;
double dum = vv[i] * abs(sum);
if ( dum >= big )
{
big = dum;
imax = i;
}
}
if ( j != imax )
{
for (int k=0; k<n; k++)
{
complex<double> cdum = a[imax][k];
a[imax][k] = a[j][k];
a[j][k] = cdum;
}
d = -d;
vv[imax] = vv[j];
}
indx[j] = imax;
if ( a[j][j].real() == 0.0 && a[j][j].imag() == 0.0 )
a[j][j] = complex<double>(1.0e-20, 1.0e-20);
if ( j != n - 1 )
{
complex<double> x = complex<double>(1.0, 0.0);
complex<double> cdum = x / a[j][j];
for (int i=j+1; i<n; i++)
a[i][j] = a[i][j] * cdum;
}
}
if ( pd != NULL )
*pd = d;
return (0);
}
/*
* This function reduces the matrix A to upper Hessenberg form.
*
* \brief Reduce A to upper Hessenberg
* \param [in/out] a Real n X n matrix [in], Upper Hessenberg matrix, with additional
* information on the transformation stored in the lower triangle.
* \param low [in] Index to first nonzero row
* \param high [in] Index to last non-xero row
* \param perm [out] Permutation vector for elemtrans
*/
void MbEigensystem::elmhes(int low, int high, MbMatrix<double> &a, MbVector<int> &perm) {
for (int m=low+1; m<high; m++)
{
int i = m;
double x = 0.0;
for (int j=m; j<=high; j++)
{
if ( fabs(a[j][m-1]) > fabs(x) )
{
x = a[j][m-1];
i = j;
}
}
perm[m] = i;
if ( i != m )
{
for (int j=m-1; j<n; j++)
{
double tempD = a[i][j];
a[i][j] = a[m][j];
a[m][j] = tempD;
}
for (int j=0; j<=high; j++)
{
double tempD = a[j][i];
a[j][i] = a[j][m];
a[j][m] = tempD;
}
}
if ( x != 0.0 )
{
for (i=m+1; i<=high; i++)
{
double y = a[i][m-1];
if ( y != 0.0 )
{
y /= x;
a[i][m-1] = y;
for (int j=m; j<n; j++)
a[i][j] -= y * a[m][j];
for (int j=0; j<=high; j++)
a[j][m] += y * a[j][i];
}
}
}
}
}
/*!
* This function copies the Hessenberg matrix stored in 'a' to 'h'.
*
* \brief Copy Hessenberg matrix
* \param a [in] Real n X n matrix
* \param low [in] Index to first nonzero row (see balance)
* \param high [in] Index to last nonzero row (see balance)
* \param perm [in] Vector of permutation data from elmhes
* \param h [out] Hessenberg matrix
*/
void MbEigensystem::elmtrans(int low, int high, MbMatrix<double> &a, MbVector<int> &perm, MbMatrix<double> &h) {
for (int i=0; i<n; i++)
{
for (int k=0; k<n; k++)
h[i][k] = 0.0;
h[i][i] = 1.0;
}
for (int i=high-1; i>low; i--)
{
int j = perm[i];
for (int k=i+1; k<=high; k++)
h[k][i] = a[k][i-1];
if ( i != j )
{
for (int k=i; k<=high; k++)
{
h[i][k] = h[j][k];
h[j][k] = 0.0;
}
h[j][i] = 1.0;
}
}
}
/*!
* Return the determinant
*
*\brief Return determinant
*\param V_ Matrix for eigenvectors
*/
double MbEigensystem::getDeterminant(void) {
double det = 1.0;
for (int i=0; i<n; i++) {
det *= realEigenvalues[i];
}
return (det);
}
/*!
* This function calculates the eigenvalues and eigenvectors of an
* n X n upper Hessenberg matrix (reduction from Hessenberg to real
* Schur form).
*
* \brief Calculate eigensystem of Hessenberg matrix
* \param h [in] Hessenberg matrix (n X n)
* \param low [in] Index to first nonzero row (see balance)
* \param high [in] Index to last nonzero row (see balance)
* \param eivec [out] Matrix which contains the eigenvectors as follows:
* For real eigenvalues the corresponding column
* contains the corresponding eigenvector, while for
* complex eigenvalues the corresponding column contains
* the real part of the eigenvector while its imaginary
* part is stored in the subsequent column of eivec.
* The eigenvector for the complex conjugate eigenvector
* is given by the complex conjugate eigenvector.
* \param wr [out] Real part of the n eigenvalues
* \param wi [out] Imaginary parts of the eigenvalues
* \return 0 on success, 1 on failure
*/
int MbEigensystem::hqr2(int low, int high, MbMatrix<double> &h, MbVector<double> &wr, MbVector<double> &wi, MbMatrix<double> &eivec) {
/* store roots isolated by balance, and compute matrix norm */
double norm = 0.0;
int k = 0;
for (int i=0; i<n; i++)
{
for (int j=k; j<n; j++)
norm += fabs(h[i][j]);
k = i;
if ((i < low) || (i > high))
{
wr[i] = h[i][i];
wi[i] = 0.0;
}
}
/* search for next eigenvalues */
int en=high, na, numIterations = n * 30;
double p, q, r, s, t=0.0, w, x, y, z;
while ( en >= low )
{
int iter = 0;
na = en - 1;
int enm2 = na - 1;
bool twoRoots = false;
for ( ; ; )
{
int l, m;
for (l=en; l>low; l--)
{
s = fabs(h[l-1][l-1]) + fabs(h[l][l]);
if (s == 0.0)
s = norm;
double tst1 = s;
double tst2 = tst1 + fabs(h[l][l-1]);
if (tst2 == tst1)
break;
}
/* form shift */
x = h[en][en];
if ( l == en )
break;
y = h[na][na];
w = h[en][na] * h[na][en];
if (l == na)
{
twoRoots = true;
break;
}
if ( numIterations == 0 )
return (en);
/* form exceptional shift */
if ( (iter == 10) || (iter == 20) )
{
t += x;
for (int i=low; i<=en; i++)
h[i][i] -= x;
s = fabs(h[en][na]) + fabs(h[na][enm2]);
x = 0.75 * s;
y = x;
w = -0.4375 * s * s;
}
iter++;
numIterations--;
/* look for two consecutive small sub-diagonal elements */
for (m=enm2; m>=l; m--)
{
z = h[m][m];
r = x - z;
s = y - z;
p = (r * s - w) / h[m+1][m] + h[m][m+1];
q = h[m+1][m+1] - z - r - s;
r = h[m+2][m+1];
s = fabs(p) + fabs(q) + fabs(r);
p /= s;
q /= s;
r /= s;
if ( m == l )
break;
double tst1 = fabs(p) * (fabs(h[m-1][m-1]) + fabs(z) + fabs(h[m+1][m+1]));
double tst2 = tst1 + fabs(h[m][m-1]) * (fabs(q) + fabs(r));
if ( tst2 == tst1 )
break;
}
int mp2 = m + 2;
for (int i=mp2; i<=en; i++)
{
h[i][i-2] = 0.0;
if ( i != mp2 )
h[i][i-3] = 0.0;
}
/* double QR step involving rows l to en and columns m to en */
for (k=m; k<=na; k++)
{
if ( k != m )
{
p = h[k][k-1];
q = h[k+1][k-1];
r = (k != na) ? h[k+2][k-1] : 0.0;
x = fabs(p) + fabs(q) + fabs(r);
if (x == 0.0)
continue;
p /= x;
q /= x;
r /= x;
}
s = sqrt(p * p + q * q + r * r);
if (p < 0.0)
s = -s;
if ( k != m )
h[k][k-1] = -s * x;
else if ( l != m )
h[k][k-1] = -h[k][k-1];
p += s;
x = p / s;
y = q / s;
z = r / s;
q /= p;
r /= p;
if ( k == na )
{
/* row modification */
for (int j=k; j<n; j++)
{
p = h[k][j] + q * h[k+1][j];
h[k][j] -= p * x;
h[k+1][j] -= p * y;
}
int stop = (k + 3 < en) ? (k + 3) : en;
/* column modification */
for (int i=0; i<=stop; i++)
{
p = x * h[i][k] + y * h[i][k+1];
h[i][k] -= p;
h[i][k+1] -= p * q;
}
/* accumulate transformations */
for (int i=low; i<=high; i++)
{
p = x * eivec[i][k] + y * eivec[i][k+1];
eivec[i][k] -= p;
eivec[i][k+1] -= p * q;
}
}
else
{
/* row modification */
for (int j=k; j<n; j++)
{
p = h[k][j] + q * h[k+1][j] + r * h[k+2][j];
h[k][j] -= p * x;
h[k+1][j] -= p * y;
h[k+2][j] -= p * z;
}
int stop = (k + 3 < en) ? (k + 3) : en;
/* column modification */
for (int i=0; i<=stop; i++)
{
p = x * h[i][k] + y * h[i][k+1] + z * h[i][k+2];
h[i][k] -= p;
h[i][k+1] -= p * q;
h[i][k+2] -= p * r;
}
/* accumulate transformations */
for (int i=low; i<=high; i++)
{
p = x * eivec[i][k] + y * eivec[i][k+1] + z * eivec[i][k+2];
eivec[i][k] -= p;
eivec[i][k+1] -= p * q;
eivec[i][k+2] -= p * r;
}
}
}
}
if (twoRoots)
{
/* two roots found */
p = (y - x) / 2.0;
q = p * p + w;
z = sqrt(fabs(q));
h[en][en] = x + t;
x = h[en][en];
h[na][na] = y + t;
if (q >= -1e-12)
{
/* real pair */
z = (p < 0.0) ? (p - z) : (p + z);
wr[na] = x + z;
wr[en] = wr[na];
if ( z != 0.0 )
wr[en] = x - w / z;
wi[na] = 0.0;
wi[en] = 0.0;
x = h[en][na];
s = fabs(x) + fabs(z);
p = x / s;
q = z / s;
r = sqrt(p*p + q*q);
p /= r;
q /= r;
/* row modification */
for (int j=na; j<n; j++)
{
z = h[na][j];
h[na][j] = q * z + p * h[en][j];
h[en][j] = q * h[en][j] - p * z;
}
/* column modification */
for (int i=0; i<=en; i++)
{
z = h[i][na];
h[i][na] = q * z + p * h[i][en];
h[i][en] = q * h[i][en] - p * z;
}
/* accumulate transformations */
for (int i=low; i<=high; i++)
{
z = eivec[i][na];
eivec[i][na] = q * z + p * eivec[i][en];
eivec[i][en] = q * eivec[i][en] - p * z;
}
}
else
{
/* complex pair */
wr[na] = x + p;
wr[en] = x + p;
wi[na] = z;
wi[en] = -z;
}
en = enm2;
}
else
{
/* one root found */
h[en][en] = x + t;
wr[en] = h[en][en];
wi[en] = 0.0;
en = na;
}
}
if (norm == 0.0)
return (0);
for (en=n-1; en>=0; en--)
{
p = wr[en];
q = wi[en];
na = en - 1;
if (q < -1e-12)
{
/* last vector component chosen imaginary so that eigenvector
matrix is triangular */
int m = na;
if (fabs(h[en][na]) > fabs(h[na][en]))
{
h[na][na] = q / h[en][na];
h[na][en] = -(h[en][en] - p) / h[en][na];
}
else
{
//complexDivision(0.0, -h[na][en], h[na][na] - p, q, &h[na][na], &h[na][en]);
complex<double> ca( 0.0, -h[na][en] );
complex<double> cb( h[na][na]-p, q );
complex<double> cc = ca / cb;
h[na][na] = cc.real();
h[na][en] = cc.imag();
}
h[en][na] = 0.0;
h[en][en] = 1.0;
int enm2 = na - 1;
if ( enm2 >= 0 )
{
for (int i=enm2; i>=0; i--)
{
w = h[i][i] - p;
double ra = 0.0;
double sa = 0.0;
for (int j=m; j<=en; j++)
{
ra += h[i][j] * h[j][na];
sa += h[i][j] * h[j][en];
}
if ( wi[i] < 0.0 )
{
z = w;
r = ra;
s = sa;
}
else
{
m = i;
if ( wi[i] == 0.0 )
{
//complexDivision(-ra, -sa, w, q, &h[i][na], &h[i][en]);
complex<double> ca( -ra, -sa );
complex<double> cb( w, q );
complex<double> cc = ca / cb;
h[i][na] = cc.real();
h[i][en] = cc.imag();
}
else
{
/* solve complex linear system: */
/* | w+i*q x | | h[i][na] + i*h[i][en] | | -ra+i*sa | */
/* | | | | = | | */
/* | y z+i*q| | h[i+1][na]+i*h[i+1][en]| | -r+i*s | */
x = h[i][i+1];
y = h[i+1][i];
double vr = (wr[i] - p) * (wr[i] - p) + wi[i] * wi[i] - q * q;
double vi = (wr[i] - p) * 2.0 * q;
if ( (vr == 0.0) && (vi == 0.0) )
{
double tst1 = norm * (fabs(w) + fabs(q) + fabs(x) + fabs(y) + fabs(z));
double tst2;
vr = tst1;
do
{
vr *= .01;
tst2 = tst1 + vr;
} while (tst2 > tst1);
}
//complexDivision(x * r - z * ra + q * sa, x * s - z * sa - q * ra, vr, vi, &h[i][na], &h[i][en]);
complex<double> ca( x * r - z * ra + q * sa, x * s - z * sa - q * ra );
complex<double> cb( vr, vi );
complex<double> cc = ca / cb;
h[i][na] = cc.real();
h[i][en] = cc.imag();
if ( fabs(x) > fabs(z) + fabs(q) )
{
h[i+1][na] = (-ra - w * h[i][na] + q * h[i][en]) / x;
h[i+1][en] = (-sa - w * h[i][en] - q * h[i][na]) / x;
}
else
{
//complexDivision(-r - y * h[i][na], -s - y * h[i][en], z, q, &h[i+1][na], &h[i+1][en]);
ca = complex<double>( -r - y * h[i][na], -s - y * h[i][en] );
cb = complex<double>( z, q );
cc = ca / cb;
h[i+1][na] = cc.real();
h[i+1][en] = cc.imag();
}
}
/* overflow control */
double tst1 = fabs(h[i][na]);
double tst2 = fabs(h[i][en]);
t = (tst2 > tst1) ? tst2 : tst1;
if (t != 0.0)
{
tst1 = t;
tst2 = tst1 + 1.0 / tst1;
if (tst2 <= tst1)
{
for (int j=i; j<=en; j++)
{
h[j][na] /= t;
h[j][en] /= t;
}
}
}
}
}
}
}
else if ( q == 0.0 )
{
/* real vector */
int m = en;
h[en][en] = 1.0;
if (na >= 0)
{
for (int i=na; i>=0; i--)
{
w = h[i][i] - p;
r = 0.0;
for (int j = m; j <= en; j++)
r += h[i][j] * h[j][en];
if ( wi[i] < 0.0 )
{
z = w;
s = r;
}
else
{
m = i;
if ( wi[i] == 0.0 )
{
t = w;
if ( t == 0.0 )
{
double tst1 = norm;
double tst2;
t = tst1;
do {
t *= .01;
tst2 = norm + t;
}
while (tst2 > tst1);
}
h[i][en] = -r / t;
}
else
{
/* solve the linear system: */
/* | w x | | h[i][en] | | -r | */
/* | | | | = | | */
/* | y z | | h[i+1][en] | | -s | */