1       SUBROUTINE DGET38( 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       DOUBLE PRECISION   RMAX( 3 )
 13 *     ..
 14 *
 15 *  Purpose
 16 *  =======
 17 *
 18 *  DGET38 tests DTRSEN, a routine for estimating condition numbers of a
 19 *  cluster of eigenvalues and/or its associated right invariant subspace
 20 *
 21 *  The test matrices are read from a file with logical unit number NIN.
 22 *
 23 *  Arguments
 24 *  ==========
 25 *
 26 *  RMAX    (output) DOUBLE PRECISION array, dimension (3)
 27 *          Values of the largest test ratios.
 28 *          RMAX(1) = largest residuals from DHST01 or comparing
 29 *                    different calls to DTRSEN
 30 *          RMAX(2) = largest error in reciprocal condition
 31 *                    numbers taking their conditioning into account
 32 *          RMAX(3) = largest error in reciprocal condition
 33 *                    numbers not taking their conditioning into
 34 *                    account (may be larger than RMAX(2))
 35 *
 36 *  LMAX    (output) INTEGER array, dimension (3)
 37 *          LMAX(i) is example number where largest test ratio
 38 *          RMAX(i) is achieved. Also:
 39 *          If DGEHRD returns INFO nonzero on example i, LMAX(1)=i
 40 *          If DHSEQR returns INFO nonzero on example i, LMAX(2)=i
 41 *          If DTRSEN returns INFO nonzero on example i, LMAX(3)=i
 42 *
 43 *  NINFO   (output) INTEGER array, dimension (3)
 44 *          NINFO(1) = No. of times DGEHRD returned INFO nonzero
 45 *          NINFO(2) = No. of times DHSEQR returned INFO nonzero
 46 *          NINFO(3) = No. of times DTRSEN returned INFO nonzero
 47 *
 48 *  KNT     (output) INTEGER
 49 *          Total number of examples tested.
 50 *
 51 *  NIN     (input) INTEGER
 52 *          Input logical unit number.
 53 *
 54 *  =====================================================================
 55 *
 56 *     .. Parameters ..
 57       DOUBLE PRECISION   ZERO, ONE, TWO
 58       PARAMETER          ( ZERO = 0.0D0, ONE = 1.0D0, TWO = 2.0D0 )
 59       DOUBLE PRECISION   EPSIN
 60       PARAMETER          ( EPSIN = 5.9605D-8 )
 61       INTEGER            LDT, LWORK
 62       PARAMETER          ( LDT = 20, LWORK = 2*LDT*10+LDT ) )
 63       INTEGER            LIWORK
 64       PARAMETER          ( LIWORK = LDT*LDT )
 65 *     ..
 66 *     .. Local Scalars ..
 67       INTEGER            I, INFO, ISCL, ITMP, J, KMIN, M, N, NDIM
 68       DOUBLE PRECISION   BIGNUM, EPS, S, SEP, SEPIN, SEPTMP, SIN,
 69      $                   SMLNUM, STMP, TNRM, TOL, TOLIN, V, VIMIN, VMAX,
 70      $                   VMUL, VRMIN
 71 *     ..
 72 *     .. Local Arrays ..
 73       LOGICAL            SELECT( LDT )
 74       INTEGER            IPNT( LDT ), ISELEC( LDT ), IWORK( LIWORK )
 75       DOUBLE PRECISION   Q( LDT, LDT ), QSAV( LDT, LDT ),
 76      $                   QTMP( LDT, LDT ), RESULT2 ), T( LDT, LDT ),
 77      $                   TMP( LDT, LDT ), TSAV( LDT, LDT ),
 78      $                   TSAV1( LDT, LDT ), TTMP( LDT, LDT ), VAL( 3 ),
 79      $                   WI( LDT ), WITMP( LDT ), WORK( LWORK ),
 80      $                   WR( LDT ), WRTMP( LDT )
 81 *     ..
 82 *     .. External Functions ..
 83       DOUBLE PRECISION   DLAMCH, DLANGE
 84       EXTERNAL           DLAMCH, DLANGE
 85 *     ..
 86 *     .. External Subroutines ..
 87       EXTERNAL           DCOPY, DGEHRD, DHSEQR, DHST01, DLABAD, DLACPY,
 88      $                   DORGHR, DSCAL, DTRSEN
 89 *     ..
 90 *     .. Intrinsic Functions ..
 91       INTRINSIC          DBLEMAXSQRT
 92 *     ..
 93 *     .. Executable Statements ..
 94 *
 95       EPS = DLAMCH( 'P' )
 96       SMLNUM = DLAMCH( 'S' ) / EPS
 97       BIGNUM = ONE / SMLNUM
 98       CALL DLABAD( SMLNUM, BIGNUM )
 99 *
100 *     EPSIN = 2**(-24) = precision to which input data computed
101 *
102       EPS = MAX( EPS, EPSIN )
103       RMAX( 1 ) = ZERO
104       RMAX( 2 ) = ZERO
105       RMAX( 3 ) = ZERO
106       LMAX( 1 ) = 0
107       LMAX( 2 ) = 0
108       LMAX( 3 ) = 0
109       KNT = 0
110       NINFO( 1 ) = 0
111       NINFO( 2 ) = 0
112       NINFO( 3 ) = 0
113 *
114       VAL( 1 ) = SQRT( SMLNUM )
115       VAL( 2 ) = ONE
116       VAL( 3 ) = SQRTSQRT( BIGNUM ) )
117 *
118 *     Read input data until N=0.  Assume input eigenvalues are sorted
119 *     lexicographically (increasing by real part, then decreasing by
120 *     imaginary part)
121 *
122    10 CONTINUE
123       READ( NIN, FMT = * )N, NDIM
124       IF( N.EQ.0 )
125      $   RETURN
126       READ( NIN, FMT = * )( ISELEC( I ), I = 1, NDIM )
127       DO 20 I = 1, N
128          READ( NIN, FMT = * )( TMP( I, J ), J = 1, N )
129    20 CONTINUE
130       READ( NIN, FMT = * )SIN, SEPIN
131 *
132       TNRM = DLANGE( 'M', N, N, TMP, LDT, WORK )
133       DO 160 ISCL = 13
134 *
135 *        Scale input matrix
136 *
137          KNT = KNT + 1
138          CALL DLACPY( 'F', N, N, TMP, LDT, T, LDT )
139          VMUL = VAL( ISCL )
140          DO 30 I = 1, N
141             CALL DSCAL( N, VMUL, T( 1, I ), 1 )
142    30    CONTINUE
143          IF( TNRM.EQ.ZERO )
144      $      VMUL = ONE
145          CALL DLACPY( 'F', N, N, T, LDT, TSAV, LDT )
146 *
147 *        Compute Schur form
148 *
149          CALL DGEHRD( N, 1, N, T, LDT, WORK( 1 ), WORK( N+1 ), LWORK-N,
150      $                INFO )
151          IF( INFO.NE.0 ) THEN
152             LMAX( 1 ) = KNT
153             NINFO( 1 ) = NINFO( 1 ) + 1
154             GO TO 160
155          END IF
156 *
157 *        Generate orthogonal matrix
158 *
159          CALL DLACPY( 'L', N, N, T, LDT, Q, LDT )
160          CALL DORGHR( N, 1, N, Q, LDT, WORK( 1 ), WORK( N+1 ), LWORK-N,
161      $                INFO )
162 *
163 *        Compute Schur form
164 *
165          CALL DHSEQR( 'S''V', N, 1, N, T, LDT, WR, WI, Q, LDT, WORK,
166      $                LWORK, INFO )
167          IF( INFO.NE.0 ) THEN
168             LMAX( 2 ) = KNT
169             NINFO( 2 ) = NINFO( 2 ) + 1
170             GO TO 160
171          END IF
172 *
173 *        Sort, select eigenvalues
174 *
175          DO 40 I = 1, N
176             IPNT( I ) = I
177             SELECT( I ) = .FALSE.
178    40    CONTINUE
179          CALL DCOPY( N, WR, 1, WRTMP, 1 )
180          CALL DCOPY( N, WI, 1, WITMP, 1 )
181          DO 60 I = 1, N - 1
182             KMIN = I
183             VRMIN = WRTMP( I )
184             VIMIN = WITMP( I )
185             DO 50 J = I + 1, N
186                IF( WRTMP( J ).LT.VRMIN ) THEN
187                   KMIN = J
188                   VRMIN = WRTMP( J )
189                   VIMIN = WITMP( J )
190                END IF
191    50       CONTINUE
192             WRTMP( KMIN ) = WRTMP( I )
193             WITMP( KMIN ) = WITMP( I )
194             WRTMP( I ) = VRMIN
195             WITMP( I ) = VIMIN
196             ITMP = IPNT( I )
197             IPNT( I ) = IPNT( KMIN )
198             IPNT( KMIN ) = ITMP
199    60    CONTINUE
200          DO 70 I = 1, NDIM
201             SELECT( IPNT( ISELEC( I ) ) ) = .TRUE.
202    70    CONTINUE
203 *
204 *        Compute condition numbers
205 *
206          CALL DLACPY( 'F', N, N, Q, LDT, QSAV, LDT )
207          CALL DLACPY( 'F', N, N, T, LDT, TSAV1, LDT )
208          CALL DTRSEN( 'B''V'SELECT, N, T, LDT, Q, LDT, WRTMP, WITMP,
209      $                M, S, SEP, WORK, LWORK, IWORK, LIWORK, INFO )
210          IF( INFO.NE.0 ) THEN
211             LMAX( 3 ) = KNT
212             NINFO( 3 ) = NINFO( 3 ) + 1
213             GO TO 160
214          END IF
215          SEPTMP = SEP / VMUL
216          STMP = S
217 *
218 *        Compute residuals
219 *
220          CALL DHST01( N, 1, N, TSAV, LDT, T, LDT, Q, LDT, WORK, LWORK,
221      $                RESULT )
222          VMAX = MAXRESULT1 ), RESULT2 ) )
223          IF( VMAX.GT.RMAX( 1 ) ) THEN
224             RMAX( 1 ) = VMAX
225             IF( NINFO( 1 ).EQ.0 )
226      $         LMAX( 1 ) = KNT
227          END IF
228 *
229 *        Compare condition number for eigenvalue cluster
230 *        taking its condition number into account
231 *
232          V = MAX( TWO*DBLE( N )*EPS*TNRM, SMLNUM )
233          IF( TNRM.EQ.ZERO )
234      $      V = ONE
235          IF( V.GT.SEPTMP ) THEN
236             TOL = ONE
237          ELSE
238             TOL = V / SEPTMP
239          END IF
240          IF( V.GT.SEPIN ) THEN
241             TOLIN = ONE
242          ELSE
243             TOLIN = V / SEPIN
244          END IF
245          TOL = MAX( TOL, SMLNUM / EPS )
246          TOLIN = MAX( TOLIN, SMLNUM / EPS )
247          IF( EPS*SIN-TOLIN ).GT.STMP+TOL ) THEN
248             VMAX = ONE / EPS
249          ELSE IFSIN-TOLIN.GT.STMP+TOL ) THEN
250             VMAX = ( SIN-TOLIN ) / ( STMP+TOL )
251          ELSE IFSIN+TOLIN.LT.EPS*( STMP-TOL ) ) THEN
252             VMAX = ONE / EPS
253          ELSE IFSIN+TOLIN.LT.STMP-TOL ) THEN
254             VMAX = ( STMP-TOL ) / ( SIN+TOLIN )
255          ELSE
256             VMAX = ONE
257          END IF
258          IF( VMAX.GT.RMAX( 2 ) ) THEN
259             RMAX( 2 ) = VMAX
260             IF( NINFO( 2 ).EQ.0 )
261      $         LMAX( 2 ) = KNT
262          END IF
263 *
264 *        Compare condition numbers for invariant subspace
265 *        taking its condition number into account
266 *
267          IF( V.GT.SEPTMP*STMP ) THEN
268             TOL = SEPTMP
269          ELSE
270             TOL = V / STMP
271          END IF
272          IF( V.GT.SEPIN*SIN ) THEN
273             TOLIN = SEPIN
274          ELSE
275             TOLIN = V / SIN
276          END IF
277          TOL = MAX( TOL, SMLNUM / EPS )
278          TOLIN = MAX( TOLIN, SMLNUM / EPS )
279          IF( EPS*( SEPIN-TOLIN ).GT.SEPTMP+TOL ) THEN
280             VMAX = ONE / EPS
281          ELSE IF( SEPIN-TOLIN.GT.SEPTMP+TOL ) THEN
282             VMAX = ( SEPIN-TOLIN ) / ( SEPTMP+TOL )
283          ELSE IF( SEPIN+TOLIN.LT.EPS*( SEPTMP-TOL ) ) THEN
284             VMAX = ONE / EPS
285          ELSE IF( SEPIN+TOLIN.LT.SEPTMP-TOL ) THEN
286             VMAX = ( SEPTMP-TOL ) / ( SEPIN+TOLIN )
287          ELSE
288             VMAX = ONE
289          END IF
290          IF( VMAX.GT.RMAX( 2 ) ) THEN
291             RMAX( 2 ) = VMAX
292             IF( NINFO( 2 ).EQ.0 )
293      $         LMAX( 2 ) = KNT
294          END IF
295 *
296 *        Compare condition number for eigenvalue cluster
297 *        without taking its condition number into account
298 *
299          IFSIN.LE.DBLE2*N )*EPS .AND. STMP.LE.DBLE2*N )*EPS ) THEN
300             VMAX = ONE
301          ELSE IF( EPS*SIN.GT.STMP ) THEN
302             VMAX = ONE / EPS
303          ELSE IFSIN.GT.STMP ) THEN
304             VMAX = SIN / STMP
305          ELSE IFSIN.LT.EPS*STMP ) THEN
306             VMAX = ONE / EPS
307          ELSE IFSIN.LT.STMP ) THEN
308             VMAX = STMP / SIN
309          ELSE
310             VMAX = ONE
311          END IF
312          IF( VMAX.GT.RMAX( 3 ) ) THEN
313             RMAX( 3 ) = VMAX
314             IF( NINFO( 3 ).EQ.0 )
315      $         LMAX( 3 ) = KNT
316          END IF
317 *
318 *        Compare condition numbers for invariant subspace
319 *        without taking its condition number into account
320 *
321          IF( SEPIN.LE..AND. SEPTMP.LE.V ) THEN
322             VMAX = ONE
323          ELSE IF( EPS*SEPIN.GT.SEPTMP ) THEN
324             VMAX = ONE / EPS
325          ELSE IF( SEPIN.GT.SEPTMP ) THEN
326             VMAX = SEPIN / SEPTMP
327          ELSE IF( SEPIN.LT.EPS*SEPTMP ) THEN
328             VMAX = ONE / EPS
329          ELSE IF( SEPIN.LT.SEPTMP ) THEN
330             VMAX = SEPTMP / SEPIN
331          ELSE
332             VMAX = ONE
333          END IF
334          IF( VMAX.GT.RMAX( 3 ) ) THEN
335             RMAX( 3 ) = VMAX
336             IF( NINFO( 3 ).EQ.0 )
337      $         LMAX( 3 ) = KNT
338          END IF
339 *
340 *        Compute eigenvalue condition number only and compare
341 *        Update Q
342 *
343          VMAX = ZERO
344          CALL DLACPY( 'F', N, N, TSAV1, LDT, TTMP, LDT )
345          CALL DLACPY( 'F', N, N, QSAV, LDT, QTMP, LDT )
346          SEPTMP = -ONE
347          STMP = -ONE
348          CALL DTRSEN( 'E''V'SELECT, N, TTMP, LDT, QTMP, LDT, WRTMP,
349      $                WITMP, M, STMP, SEPTMP, WORK, LWORK, IWORK,
350      $                LIWORK, INFO )
351          IF( INFO.NE.0 ) THEN
352             LMAX( 3 ) = KNT
353             NINFO( 3 ) = NINFO( 3 ) + 1
354             GO TO 160
355          END IF
356          IF( S.NE.STMP )
357      $      VMAX = ONE / EPS
358          IF-ONE.NE.SEPTMP )
359      $      VMAX = ONE / EPS
360          DO 90 I = 1, N
361             DO 80 J = 1, N
362                IF( TTMP( I, J ).NE.T( I, J ) )
363      $            VMAX = ONE / EPS
364                IF( QTMP( I, J ).NE.Q( I, J ) )
365      $            VMAX = ONE / EPS
366    80       CONTINUE
367    90    CONTINUE
368 *
369 *        Compute invariant subspace condition number only and compare
370 *        Update Q
371 *
372          CALL DLACPY( 'F', N, N, TSAV1, LDT, TTMP, LDT )
373          CALL DLACPY( 'F', N, N, QSAV, LDT, QTMP, LDT )
374          SEPTMP = -ONE
375          STMP = -ONE
376          CALL DTRSEN( 'V''V'SELECT, N, TTMP, LDT, QTMP, LDT, WRTMP,
377      $                WITMP, M, STMP, SEPTMP, WORK, LWORK, IWORK,
378      $                LIWORK, INFO )
379          IF( INFO.NE.0 ) THEN
380             LMAX( 3 ) = KNT
381             NINFO( 3 ) = NINFO( 3 ) + 1
382             GO TO 160
383          END IF
384          IF-ONE.NE.STMP )
385      $      VMAX = ONE / EPS
386          IF( SEP.NE.SEPTMP )
387      $      VMAX = ONE / EPS
388          DO 110 I = 1, N
389             DO 100 J = 1, N
390                IF( TTMP( I, J ).NE.T( I, J ) )
391      $            VMAX = ONE / EPS
392                IF( QTMP( I, J ).NE.Q( I, J ) )
393      $            VMAX = ONE / EPS
394   100       CONTINUE
395   110    CONTINUE
396 *
397 *        Compute eigenvalue condition number only and compare
398 *        Do not update Q
399 *
400          CALL DLACPY( 'F', N, N, TSAV1, LDT, TTMP, LDT )
401          CALL DLACPY( 'F', N, N, QSAV, LDT, QTMP, LDT )
402          SEPTMP = -ONE
403          STMP = -ONE
404          CALL DTRSEN( 'E''N'SELECT, N, TTMP, LDT, QTMP, LDT, WRTMP,
405      $                WITMP, M, STMP, SEPTMP, WORK, LWORK, IWORK,
406      $                LIWORK, INFO )
407          IF( INFO.NE.0 ) THEN
408             LMAX( 3 ) = KNT
409             NINFO( 3 ) = NINFO( 3 ) + 1
410             GO TO 160
411          END IF
412          IF( S.NE.STMP )
413      $      VMAX = ONE / EPS
414          IF-ONE.NE.SEPTMP )
415      $      VMAX = ONE / EPS
416          DO 130 I = 1, N
417             DO 120 J = 1, N
418                IF( TTMP( I, J ).NE.T( I, J ) )
419      $            VMAX = ONE / EPS
420                IF( QTMP( I, J ).NE.QSAV( I, J ) )
421      $            VMAX = ONE / EPS
422   120       CONTINUE
423   130    CONTINUE
424 *
425 *        Compute invariant subspace condition number only and compare
426 *        Do not update Q
427 *
428          CALL DLACPY( 'F', N, N, TSAV1, LDT, TTMP, LDT )
429          CALL DLACPY( 'F', N, N, QSAV, LDT, QTMP, LDT )
430          SEPTMP = -ONE
431          STMP = -ONE
432          CALL DTRSEN( 'V''N'SELECT, N, TTMP, LDT, QTMP, LDT, WRTMP,
433      $                WITMP, M, STMP, SEPTMP, WORK, LWORK, IWORK,
434      $                LIWORK, INFO )
435          IF( INFO.NE.0 ) THEN
436             LMAX( 3 ) = KNT
437             NINFO( 3 ) = NINFO( 3 ) + 1
438             GO TO 160
439          END IF
440          IF-ONE.NE.STMP )
441      $      VMAX = ONE / EPS
442          IF( SEP.NE.SEPTMP )
443      $      VMAX = ONE / EPS
444          DO 150 I = 1, N
445             DO 140 J = 1, N
446                IF( TTMP( I, J ).NE.T( I, J ) )
447      $            VMAX = ONE / EPS
448                IF( QTMP( I, J ).NE.QSAV( I, J ) )
449      $            VMAX = ONE / EPS
450   140       CONTINUE
451   150    CONTINUE
452          IF( VMAX.GT.RMAX( 1 ) ) THEN
453             RMAX( 1 ) = VMAX
454             IF( NINFO( 1 ).EQ.0 )
455      $         LMAX( 1 ) = KNT
456          END IF
457   160 CONTINUE
458       GO TO 10
459 *
460 *     End of DGET38
461 *
462       END