1       SUBROUTINE CGET37( RMAX, LMAX, NINFO, KNT, NIN )
  2 *
  3 *  -- LAPACK test routine (version 3.1) --
  4 *     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
  5 *     November 2006
  6 *
  7 *     .. Scalar Arguments ..
  8       INTEGER            KNT, NIN
  9 *     ..
 10 *     .. Array Arguments ..
 11       INTEGER            LMAX( 3 ), NINFO( 3 )
 12       REAL               RMAX( 3 )
 13 *     ..
 14 *
 15 *  Purpose
 16 *  =======
 17 *
 18 *  CGET37 tests CTRSNA, a routine for estimating condition numbers of
 19 *  eigenvalues and/or right eigenvectors of a matrix.
 20 *
 21 *  The test matrices are read from a file with logical unit number NIN.
 22 *
 23 *  Arguments
 24 *  ==========
 25 *
 26 *  RMAX    (output) REAL array, dimension (3)
 27 *          Value of the largest test ratio.
 28 *          RMAX(1) = largest ratio comparing different calls to CTRSNA
 29 *          RMAX(2) = largest error in reciprocal condition
 30 *                    numbers taking their conditioning into account
 31 *          RMAX(3) = largest error in reciprocal condition
 32 *                    numbers not taking their conditioning into
 33 *                    account (may be larger than RMAX(2))
 34 *
 35 *  LMAX    (output) INTEGER array, dimension (3)
 36 *          LMAX(i) is example number where largest test ratio
 37 *          RMAX(i) is achieved. Also:
 38 *          If CGEHRD returns INFO nonzero on example i, LMAX(1)=i
 39 *          If CHSEQR returns INFO nonzero on example i, LMAX(2)=i
 40 *          If CTRSNA returns INFO nonzero on example i, LMAX(3)=i
 41 *
 42 *  NINFO   (output) INTEGER array, dimension (3)
 43 *          NINFO(1) = No. of times CGEHRD returned INFO nonzero
 44 *          NINFO(2) = No. of times CHSEQR returned INFO nonzero
 45 *          NINFO(3) = No. of times CTRSNA returned INFO nonzero
 46 *
 47 *  KNT     (output) INTEGER
 48 *          Total number of examples tested.
 49 *
 50 *  NIN     (input) INTEGER
 51 *          Input logical unit number
 52 *
 53 *  =====================================================================
 54 *
 55 *     .. Parameters ..
 56       REAL               ZERO, ONE, TWO
 57       PARAMETER          ( ZERO = 0.0E0, ONE = 1.0E0, TWO = 2.0E0 )
 58       REAL               EPSIN
 59       PARAMETER          ( EPSIN = 5.9605E-8 )
 60       INTEGER            LDT, LWORK
 61       PARAMETER          ( LDT = 20, LWORK = 2*LDT*10+LDT ) )
 62 *     ..
 63 *     .. Local Scalars ..
 64       INTEGER            I, ICMP, INFO, ISCL, ISRT, J, KMIN, M, N
 65       REAL               BIGNUM, EPS, SMLNUM, TNRM, TOL, TOLIN, V,
 66      $                   VCMIN, VMAX, VMIN, VMUL
 67 *     ..
 68 *     .. Local Arrays ..
 69       LOGICAL            SELECT( LDT )
 70       INTEGER            LCMP( 3 )
 71       REAL               DUM( 1 ), RWORK( 2*LDT ), S( LDT ), SEP( LDT ),
 72      $                   SEPIN( LDT ), SEPTMP( LDT ), SIN( LDT ),
 73      $                   STMP( LDT ), VAL( 3 ), WIIN( LDT ),
 74      $                   WRIN( LDT ), WSRT( LDT )
 75       COMPLEX            CDUM( 1 ), LE( LDT, LDT ), RE( LDT, LDT ),
 76      $                   T( LDT, LDT ), TMP( LDT, LDT ), W( LDT ),
 77      $                   WORK( LWORK ), WTMP( LDT )
 78 *     ..
 79 *     .. External Functions ..
 80       REAL               CLANGE, SLAMCH
 81       EXTERNAL           CLANGE, SLAMCH
 82 *     ..
 83 *     .. External Subroutines ..
 84       EXTERNAL           CCOPY, CGEHRD, CHSEQR, CLACPY, CSSCAL, CTREVC,
 85      $                   CTRSNA, SCOPY, SLABAD, SSCAL
 86 *     ..
 87 *     .. Intrinsic Functions ..
 88       INTRINSIC          AIMAGMAX, REAL, SQRT
 89 *     ..
 90 *     .. Executable Statements ..
 91 *
 92       EPS = SLAMCH( 'P' )
 93       SMLNUM = SLAMCH( 'S' ) / EPS
 94       BIGNUM = ONE / SMLNUM
 95       CALL SLABAD( SMLNUM, BIGNUM )
 96 *
 97 *     EPSIN = 2**(-24) = precision to which input data computed
 98 *
 99       EPS = MAX( EPS, EPSIN )
100       RMAX( 1 ) = ZERO
101       RMAX( 2 ) = ZERO
102       RMAX( 3 ) = ZERO
103       LMAX( 1 ) = 0
104       LMAX( 2 ) = 0
105       LMAX( 3 ) = 0
106       KNT = 0
107       NINFO( 1 ) = 0
108       NINFO( 2 ) = 0
109       NINFO( 3 ) = 0
110       VAL( 1 ) = SQRT( SMLNUM )
111       VAL( 2 ) = ONE
112       VAL( 3 ) = SQRT( BIGNUM )
113 *
114 *     Read input data until N=0.  Assume input eigenvalues are sorted
115 *     lexicographically (increasing by real part if ISRT = 0,
116 *     increasing by imaginary part if ISRT = 1)
117 *
118    10 CONTINUE
119       READ( NIN, FMT = * )N, ISRT
120       IF( N.EQ.0 )
121      $   RETURN
122       DO 20 I = 1, N
123          READ( NIN, FMT = * )( TMP( I, J ), J = 1, N )
124    20 CONTINUE
125       DO 30 I = 1, N
126          READ( NIN, FMT = * )WRIN( I ), WIIN( I ), SIN( I ), SEPIN( I )
127    30 CONTINUE
128       TNRM = CLANGE( 'M', N, N, TMP, LDT, RWORK )
129       DO 260 ISCL = 13
130 *
131 *        Scale input matrix
132 *
133          KNT = KNT + 1
134          CALL CLACPY( 'F', N, N, TMP, LDT, T, LDT )
135          VMUL = VAL( ISCL )
136          DO 40 I = 1, N
137             CALL CSSCAL( N, VMUL, T( 1, I ), 1 )
138    40    CONTINUE
139          IF( TNRM.EQ.ZERO )
140      $      VMUL = ONE
141 *
142 *        Compute eigenvalues and eigenvectors
143 *
144          CALL CGEHRD( N, 1, N, T, LDT, WORK( 1 ), WORK( N+1 ), LWORK-N,
145      $                INFO )
146          IF( INFO.NE.0 ) THEN
147             LMAX( 1 ) = KNT
148             NINFO( 1 ) = NINFO( 1 ) + 1
149             GO TO 260
150          END IF
151          DO 60 J = 1, N - 2
152             DO 50 I = J + 2, N
153                T( I, J ) = ZERO
154    50       CONTINUE
155    60    CONTINUE
156 *
157 *        Compute Schur form
158 *
159          CALL CHSEQR( 'S''N', N, 1, N, T, LDT, W, CDUM, 1, WORK,
160      $                LWORK, INFO )
161          IF( INFO.NE.0 ) THEN
162             LMAX( 2 ) = KNT
163             NINFO( 2 ) = NINFO( 2 ) + 1
164             GO TO 260
165          END IF
166 *
167 *        Compute eigenvectors
168 *
169          DO 70 I = 1, N
170             SELECT( I ) = .TRUE.
171    70    CONTINUE
172          CALL CTREVC( 'B''A'SELECT, N, T, LDT, LE, LDT, RE, LDT, N,
173      $                M, WORK, RWORK, INFO )
174 *
175 *        Compute condition numbers
176 *
177          CALL CTRSNA( 'B''A'SELECT, N, T, LDT, LE, LDT, RE, LDT, S,
178      $                SEP, N, M, WORK, N, RWORK, INFO )
179          IF( INFO.NE.0 ) THEN
180             LMAX( 3 ) = KNT
181             NINFO( 3 ) = NINFO( 3 ) + 1
182             GO TO 260
183          END IF
184 *
185 *        Sort eigenvalues and condition numbers lexicographically
186 *        to compare with inputs
187 *
188          CALL CCOPY( N, W, 1, WTMP, 1 )
189          IF( ISRT.EQ.0 ) THEN
190 *
191 *           Sort by increasing real part
192 *
193             DO 80 I = 1, N
194                WSRT( I ) = REAL( W( I ) )
195    80       CONTINUE
196          ELSE
197 *
198 *           Sort by increasing imaginary part
199 *
200             DO 90 I = 1, N
201                WSRT( I ) = AIMAG( W( I ) )
202    90       CONTINUE
203          END IF
204          CALL SCOPY( N, S, 1, STMP, 1 )
205          CALL SCOPY( N, SEP, 1, SEPTMP, 1 )
206          CALL SSCAL( N, ONE / VMUL, SEPTMP, 1 )
207          DO 110 I = 1, N - 1
208             KMIN = I
209             VMIN = WSRT( I )
210             DO 100 J = I + 1, N
211                IF( WSRT( J ).LT.VMIN ) THEN
212                   KMIN = J
213                   VMIN = WSRT( J )
214                END IF
215   100       CONTINUE
216             WSRT( KMIN ) = WSRT( I )
217             WSRT( I ) = VMIN
218             VCMIN = WTMP( I )
219             WTMP( I ) = W( KMIN )
220             WTMP( KMIN ) = VCMIN
221             VMIN = STMP( KMIN )
222             STMP( KMIN ) = STMP( I )
223             STMP( I ) = VMIN
224             VMIN = SEPTMP( KMIN )
225             SEPTMP( KMIN ) = SEPTMP( I )
226             SEPTMP( I ) = VMIN
227   110    CONTINUE
228 *
229 *        Compare condition numbers for eigenvalues
230 *        taking their condition numbers into account
231 *
232          V = MAX( TWO*REAL( N )*EPS*TNRM, SMLNUM )
233          IF( TNRM.EQ.ZERO )
234      $      V = ONE
235          DO 120 I = 1, N
236             IF( V.GT.SEPTMP( I ) ) THEN
237                TOL = ONE
238             ELSE
239                TOL = V / SEPTMP( I )
240             END IF
241             IF( V.GT.SEPIN( I ) ) THEN
242                TOLIN = ONE
243             ELSE
244                TOLIN = V / SEPIN( I )
245             END IF
246             TOL = MAX( TOL, SMLNUM / EPS )
247             TOLIN = MAX( TOLIN, SMLNUM / EPS )
248             IF( EPS*SIN( I )-TOLIN ).GT.STMP( I )+TOL ) THEN
249                VMAX = ONE / EPS
250             ELSE IFSIN( I )-TOLIN.GT.STMP( I )+TOL ) THEN
251                VMAX = ( SIN( I )-TOLIN ) / ( STMP( I )+TOL )
252             ELSE IFSIN( I )+TOLIN.LT.EPS*( STMP( I )-TOL ) ) THEN
253                VMAX = ONE / EPS
254             ELSE IFSIN( I )+TOLIN.LT.STMP( I )-TOL ) THEN
255                VMAX = ( STMP( I )-TOL ) / ( SIN( I )+TOLIN )
256             ELSE
257                VMAX = ONE
258             END IF
259             IF( VMAX.GT.RMAX( 2 ) ) THEN
260                RMAX( 2 ) = VMAX
261                IF( NINFO( 2 ).EQ.0 )
262      $            LMAX( 2 ) = KNT
263             END IF
264   120    CONTINUE
265 *
266 *        Compare condition numbers for eigenvectors
267 *        taking their condition numbers into account
268 *
269          DO 130 I = 1, N
270             IF( V.GT.SEPTMP( I )*STMP( I ) ) THEN
271                TOL = SEPTMP( I )
272             ELSE
273                TOL = V / STMP( I )
274             END IF
275             IF( V.GT.SEPIN( I )*SIN( I ) ) THEN
276                TOLIN = SEPIN( I )
277             ELSE
278                TOLIN = V / SIN( I )
279             END IF
280             TOL = MAX( TOL, SMLNUM / EPS )
281             TOLIN = MAX( TOLIN, SMLNUM / EPS )
282             IF( EPS*( SEPIN( I )-TOLIN ).GT.SEPTMP( I )+TOL ) THEN
283                VMAX = ONE / EPS
284             ELSE IF( SEPIN( I )-TOLIN.GT.SEPTMP( I )+TOL ) THEN
285                VMAX = ( SEPIN( I )-TOLIN ) / ( SEPTMP( I )+TOL )
286             ELSE IF( SEPIN( I )+TOLIN.LT.EPS*( SEPTMP( I )-TOL ) ) THEN
287                VMAX = ONE / EPS
288             ELSE IF( SEPIN( I )+TOLIN.LT.SEPTMP( I )-TOL ) THEN
289                VMAX = ( SEPTMP( I )-TOL ) / ( SEPIN( I )+TOLIN )
290             ELSE
291                VMAX = ONE
292             END IF
293             IF( VMAX.GT.RMAX( 2 ) ) THEN
294                RMAX( 2 ) = VMAX
295                IF( NINFO( 2 ).EQ.0 )
296      $            LMAX( 2 ) = KNT
297             END IF
298   130    CONTINUE
299 *
300 *        Compare condition numbers for eigenvalues
301 *        without taking their condition numbers into account
302 *
303          DO 140 I = 1, N
304             IFSIN( I ).LE.REAL2*N )*EPS .AND. STMP( I ).LE.
305      $          REAL2*N )*EPS ) THEN
306                VMAX = ONE
307             ELSE IF( EPS*SIN( I ).GT.STMP( I ) ) THEN
308                VMAX = ONE / EPS
309             ELSE IFSIN( I ).GT.STMP( I ) ) THEN
310                VMAX = SIN( I ) / STMP( I )
311             ELSE IFSIN( I ).LT.EPS*STMP( I ) ) THEN
312                VMAX = ONE / EPS
313             ELSE IFSIN( I ).LT.STMP( I ) ) THEN
314                VMAX = STMP( I ) / SIN( I )
315             ELSE
316                VMAX = ONE
317             END IF
318             IF( VMAX.GT.RMAX( 3 ) ) THEN
319                RMAX( 3 ) = VMAX
320                IF( NINFO( 3 ).EQ.0 )
321      $            LMAX( 3 ) = KNT
322             END IF
323   140    CONTINUE
324 *
325 *        Compare condition numbers for eigenvectors
326 *        without taking their condition numbers into account
327 *
328          DO 150 I = 1, N
329             IF( SEPIN( I ).LE..AND. SEPTMP( I ).LE.V ) THEN
330                VMAX = ONE
331             ELSE IF( EPS*SEPIN( I ).GT.SEPTMP( I ) ) THEN
332                VMAX = ONE / EPS
333             ELSE IF( SEPIN( I ).GT.SEPTMP( I ) ) THEN
334                VMAX = SEPIN( I ) / SEPTMP( I )
335             ELSE IF( SEPIN( I ).LT.EPS*SEPTMP( I ) ) THEN
336                VMAX = ONE / EPS
337             ELSE IF( SEPIN( I ).LT.SEPTMP( I ) ) THEN
338                VMAX = SEPTMP( I ) / SEPIN( I )
339             ELSE
340                VMAX = ONE
341             END IF
342             IF( VMAX.GT.RMAX( 3 ) ) THEN
343                RMAX( 3 ) = VMAX
344                IF( NINFO( 3 ).EQ.0 )
345      $            LMAX( 3 ) = KNT
346             END IF
347   150    CONTINUE
348 *
349 *        Compute eigenvalue condition numbers only and compare
350 *
351          VMAX = ZERO
352          DUM( 1 ) = -ONE
353          CALL SCOPY( N, DUM, 0, STMP, 1 )
354          CALL SCOPY( N, DUM, 0, SEPTMP, 1 )
355          CALL CTRSNA( 'E''A'SELECT, N, T, LDT, LE, LDT, RE, LDT,
356      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
357          IF( INFO.NE.0 ) THEN
358             LMAX( 3 ) = KNT
359             NINFO( 3 ) = NINFO( 3 ) + 1
360             GO TO 260
361          END IF
362          DO 160 I = 1, N
363             IF( STMP( I ).NE.S( I ) )
364      $         VMAX = ONE / EPS
365             IF( SEPTMP( I ).NE.DUM( 1 ) )
366      $         VMAX = ONE / EPS
367   160    CONTINUE
368 *
369 *        Compute eigenvector condition numbers only and compare
370 *
371          CALL SCOPY( N, DUM, 0, STMP, 1 )
372          CALL SCOPY( N, DUM, 0, SEPTMP, 1 )
373          CALL CTRSNA( 'V''A'SELECT, N, T, LDT, LE, LDT, RE, LDT,
374      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
375          IF( INFO.NE.0 ) THEN
376             LMAX( 3 ) = KNT
377             NINFO( 3 ) = NINFO( 3 ) + 1
378             GO TO 260
379          END IF
380          DO 170 I = 1, N
381             IF( STMP( I ).NE.DUM( 1 ) )
382      $         VMAX = ONE / EPS
383             IF( SEPTMP( I ).NE.SEP( I ) )
384      $         VMAX = ONE / EPS
385   170    CONTINUE
386 *
387 *        Compute all condition numbers using SELECT and compare
388 *
389          DO 180 I = 1, N
390             SELECT( I ) = .TRUE.
391   180    CONTINUE
392          CALL SCOPY( N, DUM, 0, STMP, 1 )
393          CALL SCOPY( N, DUM, 0, SEPTMP, 1 )
394          CALL CTRSNA( 'B''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
395      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
396          IF( INFO.NE.0 ) THEN
397             LMAX( 3 ) = KNT
398             NINFO( 3 ) = NINFO( 3 ) + 1
399             GO TO 260
400          END IF
401          DO 190 I = 1, N
402             IF( SEPTMP( I ).NE.SEP( I ) )
403      $         VMAX = ONE / EPS
404             IF( STMP( I ).NE.S( I ) )
405      $         VMAX = ONE / EPS
406   190    CONTINUE
407 *
408 *        Compute eigenvalue condition numbers using SELECT and compare
409 *
410          CALL SCOPY( N, DUM, 0, STMP, 1 )
411          CALL SCOPY( N, DUM, 0, SEPTMP, 1 )
412          CALL CTRSNA( 'E''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
413      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
414          IF( INFO.NE.0 ) THEN
415             LMAX( 3 ) = KNT
416             NINFO( 3 ) = NINFO( 3 ) + 1
417             GO TO 260
418          END IF
419          DO 200 I = 1, N
420             IF( STMP( I ).NE.S( I ) )
421      $         VMAX = ONE / EPS
422             IF( SEPTMP( I ).NE.DUM( 1 ) )
423      $         VMAX = ONE / EPS
424   200    CONTINUE
425 *
426 *        Compute eigenvector condition numbers using SELECT and compare
427 *
428          CALL SCOPY( N, DUM, 0, STMP, 1 )
429          CALL SCOPY( N, DUM, 0, SEPTMP, 1 )
430          CALL CTRSNA( 'V''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
431      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
432          IF( INFO.NE.0 ) THEN
433             LMAX( 3 ) = KNT
434             NINFO( 3 ) = NINFO( 3 ) + 1
435             GO TO 260
436          END IF
437          DO 210 I = 1, N
438             IF( STMP( I ).NE.DUM( 1 ) )
439      $         VMAX = ONE / EPS
440             IF( SEPTMP( I ).NE.SEP( I ) )
441      $         VMAX = ONE / EPS
442   210    CONTINUE
443          IF( VMAX.GT.RMAX( 1 ) ) THEN
444             RMAX( 1 ) = VMAX
445             IF( NINFO( 1 ).EQ.0 )
446      $         LMAX( 1 ) = KNT
447          END IF
448 *
449 *        Select second and next to last eigenvalues
450 *
451          DO 220 I = 1, N
452             SELECT( I ) = .FALSE.
453   220    CONTINUE
454          ICMP = 0
455          IF( N.GT.1 ) THEN
456             ICMP = 1
457             LCMP( 1 ) = 2
458             SELECT2 ) = .TRUE.
459             CALL CCOPY( N, RE( 12 ), 1, RE( 11 ), 1 )
460             CALL CCOPY( N, LE( 12 ), 1, LE( 11 ), 1 )
461          END IF
462          IF( N.GT.3 ) THEN
463             ICMP = 2
464             LCMP( 2 ) = N - 1
465             SELECT( N-1 ) = .TRUE.
466             CALL CCOPY( N, RE( 1, N-1 ), 1, RE( 12 ), 1 )
467             CALL CCOPY( N, LE( 1, N-1 ), 1, LE( 12 ), 1 )
468          END IF
469 *
470 *        Compute all selected condition numbers
471 *
472          CALL SCOPY( ICMP, DUM, 0, STMP, 1 )
473          CALL SCOPY( ICMP, DUM, 0, SEPTMP, 1 )
474          CALL CTRSNA( 'B''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
475      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
476          IF( INFO.NE.0 ) THEN
477             LMAX( 3 ) = KNT
478             NINFO( 3 ) = NINFO( 3 ) + 1
479             GO TO 260
480          END IF
481          DO 230 I = 1, ICMP
482             J = LCMP( I )
483             IF( SEPTMP( I ).NE.SEP( J ) )
484      $         VMAX = ONE / EPS
485             IF( STMP( I ).NE.S( J ) )
486      $         VMAX = ONE / EPS
487   230    CONTINUE
488 *
489 *        Compute selected eigenvalue condition numbers
490 *
491          CALL SCOPY( ICMP, DUM, 0, STMP, 1 )
492          CALL SCOPY( ICMP, DUM, 0, SEPTMP, 1 )
493          CALL CTRSNA( 'E''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
494      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
495          IF( INFO.NE.0 ) THEN
496             LMAX( 3 ) = KNT
497             NINFO( 3 ) = NINFO( 3 ) + 1
498             GO TO 260
499          END IF
500          DO 240 I = 1, ICMP
501             J = LCMP( I )
502             IF( STMP( I ).NE.S( J ) )
503      $         VMAX = ONE / EPS
504             IF( SEPTMP( I ).NE.DUM( 1 ) )
505      $         VMAX = ONE / EPS
506   240    CONTINUE
507 *
508 *        Compute selected eigenvector condition numbers
509 *
510          CALL SCOPY( ICMP, DUM, 0, STMP, 1 )
511          CALL SCOPY( ICMP, DUM, 0, SEPTMP, 1 )
512          CALL CTRSNA( 'V''S'SELECT, N, T, LDT, LE, LDT, RE, LDT,
513      $                STMP, SEPTMP, N, M, WORK, N, RWORK, INFO )
514          IF( INFO.NE.0 ) THEN
515             LMAX( 3 ) = KNT
516             NINFO( 3 ) = NINFO( 3 ) + 1
517             GO TO 260
518          END IF
519          DO 250 I = 1, ICMP
520             J = LCMP( I )
521             IF( STMP( I ).NE.DUM( 1 ) )
522      $         VMAX = ONE / EPS
523             IF( SEPTMP( I ).NE.SEP( J ) )
524      $         VMAX = ONE / EPS
525   250    CONTINUE
526          IF( VMAX.GT.RMAX( 1 ) ) THEN
527             RMAX( 1 ) = VMAX
528             IF( NINFO( 1 ).EQ.0 )
529      $         LMAX( 1 ) = KNT
530          END IF
531   260 CONTINUE
532       GO TO 10
533 *
534 *     End of CGET37
535 *
536       END