1*> \brief \b SCHKTB
2*
3*  =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6*            http://www.netlib.org/lapack/explore-html/
7*
8*  Definition:
9*  ===========
10*
11*       SUBROUTINE SCHKTB( DOTYPE, NN, NVAL, NNS, NSVAL, THRESH, TSTERR,
12*                          NMAX, AB, AINV, B, X, XACT, WORK, RWORK, IWORK,
13*                          NOUT )
14*
15*       .. Scalar Arguments ..
16*       LOGICAL            TSTERR
17*       INTEGER            NMAX, NN, NNS, NOUT
18*       REAL               THRESH
19*       ..
20*       .. Array Arguments ..
21*       LOGICAL            DOTYPE( * )
22*       INTEGER            IWORK( * ), NSVAL( * ), NVAL( * )
23*       REAL               AB( * ), AINV( * ), B( * ), RWORK( * ),
24*      $                   WORK( * ), X( * ), XACT( * )
25*       ..
26*
27*
28*> \par Purpose:
29*  =============
30*>
31*> \verbatim
32*>
33*> SCHKTB tests STBTRS, -RFS, and -CON, and SLATBS.
34*> \endverbatim
35*
36*  Arguments:
37*  ==========
38*
39*> \param[in] DOTYPE
40*> \verbatim
41*>          DOTYPE is LOGICAL array, dimension (NTYPES)
42*>          The matrix types to be used for testing.  Matrices of type j
43*>          (for 1 <= j <= NTYPES) are used for testing if DOTYPE(j) =
44*>          .TRUE.; if DOTYPE(j) = .FALSE., then type j is not used.
45*> \endverbatim
46*>
47*> \param[in] NN
48*> \verbatim
49*>          NN is INTEGER
50*>          The number of values of N contained in the vector NVAL.
51*> \endverbatim
52*>
53*> \param[in] NVAL
54*> \verbatim
55*>          NVAL is INTEGER array, dimension (NN)
56*>          The values of the matrix column dimension N.
57*> \endverbatim
58*>
59*> \param[in] NNS
60*> \verbatim
61*>          NNS is INTEGER
62*>          The number of values of NRHS contained in the vector NSVAL.
63*> \endverbatim
64*>
65*> \param[in] NSVAL
66*> \verbatim
67*>          NSVAL is INTEGER array, dimension (NNS)
68*>          The values of the number of right hand sides NRHS.
69*> \endverbatim
70*>
71*> \param[in] THRESH
72*> \verbatim
73*>          THRESH is REAL
74*>          The threshold value for the test ratios.  A result is
75*>          included in the output file if RESULT >= THRESH.  To have
76*>          every test ratio printed, use THRESH = 0.
77*> \endverbatim
78*>
79*> \param[in] TSTERR
80*> \verbatim
81*>          TSTERR is LOGICAL
82*>          Flag that indicates whether error exits are to be tested.
83*> \endverbatim
84*>
85*> \param[in] NMAX
86*> \verbatim
87*>          NMAX is INTEGER
88*>          The leading dimension of the work arrays.
89*>          NMAX >= the maximum value of N in NVAL.
90*> \endverbatim
91*>
92*> \param[out] AB
93*> \verbatim
94*>          AB is REAL array, dimension (NMAX*NMAX)
95*> \endverbatim
96*>
97*> \param[out] AINV
98*> \verbatim
99*>          AINV is REAL array, dimension (NMAX*NMAX)
100*> \endverbatim
101*>
102*> \param[out] B
103*> \verbatim
104*>          B is REAL array, dimension (NMAX*NSMAX)
105*>          where NSMAX is the largest entry in NSVAL.
106*> \endverbatim
107*>
108*> \param[out] X
109*> \verbatim
110*>          X is REAL array, dimension (NMAX*NSMAX)
111*> \endverbatim
112*>
113*> \param[out] XACT
114*> \verbatim
115*>          XACT is REAL array, dimension (NMAX*NSMAX)
116*> \endverbatim
117*>
118*> \param[out] WORK
119*> \verbatim
120*>          WORK is REAL array, dimension
121*>                      (NMAX*max(3,NSMAX))
122*> \endverbatim
123*>
124*> \param[out] RWORK
125*> \verbatim
126*>          RWORK is REAL array, dimension
127*>                      (max(NMAX,2*NSMAX))
128*> \endverbatim
129*>
130*> \param[out] IWORK
131*> \verbatim
132*>          IWORK is INTEGER array, dimension (NMAX)
133*> \endverbatim
134*>
135*> \param[in] NOUT
136*> \verbatim
137*>          NOUT is INTEGER
138*>          The unit number for output.
139*> \endverbatim
140*
141*  Authors:
142*  ========
143*
144*> \author Univ. of Tennessee
145*> \author Univ. of California Berkeley
146*> \author Univ. of Colorado Denver
147*> \author NAG Ltd.
148*
149*> \ingroup single_lin
150*
151*  =====================================================================
152      SUBROUTINE SCHKTB( DOTYPE, NN, NVAL, NNS, NSVAL, THRESH, TSTERR,
153     $                   NMAX, AB, AINV, B, X, XACT, WORK, RWORK, IWORK,
154     $                   NOUT )
155*
156*  -- LAPACK test routine --
157*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
158*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
159*
160*     .. Scalar Arguments ..
161      LOGICAL            TSTERR
162      INTEGER            NMAX, NN, NNS, NOUT
163      REAL               THRESH
164*     ..
165*     .. Array Arguments ..
166      LOGICAL            DOTYPE( * )
167      INTEGER            IWORK( * ), NSVAL( * ), NVAL( * )
168      REAL               AB( * ), AINV( * ), B( * ), RWORK( * ),
169     $                   WORK( * ), X( * ), XACT( * )
170*     ..
171*
172*  =====================================================================
173*
174*     .. Parameters ..
175      INTEGER            NTYPE1, NTYPES
176      PARAMETER          ( NTYPE1 = 9, NTYPES = 17 )
177      INTEGER            NTESTS
178      PARAMETER          ( NTESTS = 8 )
179      INTEGER            NTRAN
180      PARAMETER          ( NTRAN = 3 )
181      REAL               ONE, ZERO
182      PARAMETER          ( ONE = 1.0E+0, ZERO = 0.0E+0 )
183*     ..
184*     .. Local Scalars ..
185      CHARACTER          DIAG, NORM, TRANS, UPLO, XTYPE
186      CHARACTER*3        PATH
187      INTEGER            I, IDIAG, IK, IMAT, IN, INFO, IRHS, ITRAN,
188     $                   IUPLO, J, K, KD, LDA, LDAB, N, NERRS, NFAIL,
189     $                   NIMAT, NIMAT2, NK, NRHS, NRUN
190      REAL               AINVNM, ANORM, RCOND, RCONDC, RCONDI, RCONDO,
191     $                   SCALE
192*     ..
193*     .. Local Arrays ..
194      CHARACTER          TRANSS( NTRAN ), UPLOS( 2 )
195      INTEGER            ISEED( 4 ), ISEEDY( 4 )
196      REAL               RESULT( NTESTS )
197*     ..
198*     .. External Functions ..
199      LOGICAL            LSAME
200      REAL               SLANTB, SLANTR
201      EXTERNAL           LSAME, SLANTB, SLANTR
202*     ..
203*     .. External Subroutines ..
204      EXTERNAL           ALAERH, ALAHD, ALASUM, SCOPY, SERRTR, SGET04,
205     $                   SLACPY, SLARHS, SLASET, SLATBS, SLATTB, STBCON,
206     $                   STBRFS, STBSV, STBT02, STBT03, STBT05, STBT06,
207     $                   STBTRS
208*     ..
209*     .. Scalars in Common ..
210      LOGICAL            LERR, OK
211      CHARACTER*32       SRNAMT
212      INTEGER            INFOT, IOUNIT
213*     ..
214*     .. Common blocks ..
215      COMMON             / INFOC / INFOT, IOUNIT, OK, LERR
216      COMMON             / SRNAMC / SRNAMT
217*     ..
218*     .. Intrinsic Functions ..
219      INTRINSIC          MAX, MIN
220*     ..
221*     .. Data statements ..
222      DATA               ISEEDY / 1988, 1989, 1990, 1991 /
223      DATA               UPLOS / 'U', 'L' / , TRANSS / 'N', 'T', 'C' /
224*     ..
225*     .. Executable Statements ..
226*
227*     Initialize constants and the random number seed.
228*
229      PATH( 1: 1 ) = 'Single precision'
230      PATH( 2: 3 ) = 'TB'
231      NRUN = 0
232      NFAIL = 0
233      NERRS = 0
234      DO 10 I = 1, 4
235         ISEED( I ) = ISEEDY( I )
236   10 CONTINUE
237*
238*     Test the error exits
239*
240      IF( TSTERR )
241     $   CALL SERRTR( PATH, NOUT )
242      INFOT = 0
243*
244      DO 140 IN = 1, NN
245*
246*        Do for each value of N in NVAL
247*
248         N = NVAL( IN )
249         LDA = MAX( 1, N )
250         XTYPE = 'N'
251         NIMAT = NTYPE1
252         NIMAT2 = NTYPES
253         IF( N.LE.0 ) THEN
254            NIMAT = 1
255            NIMAT2 = NTYPE1 + 1
256         END IF
257*
258         NK = MIN( N+1, 4 )
259         DO 130 IK = 1, NK
260*
261*           Do for KD = 0, N, (3N-1)/4, and (N+1)/4. This order makes
262*           it easier to skip redundant values for small values of N.
263*
264            IF( IK.EQ.1 ) THEN
265               KD = 0
266            ELSE IF( IK.EQ.2 ) THEN
267               KD = MAX( N, 0 )
268            ELSE IF( IK.EQ.3 ) THEN
269               KD = ( 3*N-1 ) / 4
270            ELSE IF( IK.EQ.4 ) THEN
271               KD = ( N+1 ) / 4
272            END IF
273            LDAB = KD + 1
274*
275            DO 90 IMAT = 1, NIMAT
276*
277*              Do the tests only if DOTYPE( IMAT ) is true.
278*
279               IF( .NOT.DOTYPE( IMAT ) )
280     $            GO TO 90
281*
282               DO 80 IUPLO = 1, 2
283*
284*                 Do first for UPLO = 'U', then for UPLO = 'L'
285*
286                  UPLO = UPLOS( IUPLO )
287*
288*                 Call SLATTB to generate a triangular test matrix.
289*
290                  SRNAMT = 'SLATTB'
291                  CALL SLATTB( IMAT, UPLO, 'No transpose', DIAG, ISEED,
292     $                         N, KD, AB, LDAB, X, WORK, INFO )
293*
294*                 Set IDIAG = 1 for non-unit matrices, 2 for unit.
295*
296                  IF( LSAME( DIAG, 'N' ) ) THEN
297                     IDIAG = 1
298                  ELSE
299                     IDIAG = 2
300                  END IF
301*
302*                 Form the inverse of A so we can get a good estimate
303*                 of RCONDC = 1/(norm(A) * norm(inv(A))).
304*
305                  CALL SLASET( 'Full', N, N, ZERO, ONE, AINV, LDA )
306                  IF( LSAME( UPLO, 'U' ) ) THEN
307                     DO 20 J = 1, N
308                        CALL STBSV( UPLO, 'No transpose', DIAG, J, KD,
309     $                              AB, LDAB, AINV( ( J-1 )*LDA+1 ), 1 )
310   20                CONTINUE
311                  ELSE
312                     DO 30 J = 1, N
313                        CALL STBSV( UPLO, 'No transpose', DIAG, N-J+1,
314     $                              KD, AB( ( J-1 )*LDAB+1 ), LDAB,
315     $                              AINV( ( J-1 )*LDA+J ), 1 )
316   30                CONTINUE
317                  END IF
318*
319*                 Compute the 1-norm condition number of A.
320*
321                  ANORM = SLANTB( '1', UPLO, DIAG, N, KD, AB, LDAB,
322     $                    RWORK )
323                  AINVNM = SLANTR( '1', UPLO, DIAG, N, N, AINV, LDA,
324     $                     RWORK )
325                  IF( ANORM.LE.ZERO .OR. AINVNM.LE.ZERO ) THEN
326                     RCONDO = ONE
327                  ELSE
328                     RCONDO = ( ONE / ANORM ) / AINVNM
329                  END IF
330*
331*                 Compute the infinity-norm condition number of A.
332*
333                  ANORM = SLANTB( 'I', UPLO, DIAG, N, KD, AB, LDAB,
334     $                    RWORK )
335                  AINVNM = SLANTR( 'I', UPLO, DIAG, N, N, AINV, LDA,
336     $                     RWORK )
337                  IF( ANORM.LE.ZERO .OR. AINVNM.LE.ZERO ) THEN
338                     RCONDI = ONE
339                  ELSE
340                     RCONDI = ( ONE / ANORM ) / AINVNM
341                  END IF
342*
343                  DO 60 IRHS = 1, NNS
344                     NRHS = NSVAL( IRHS )
345                     XTYPE = 'N'
346*
347                     DO 50 ITRAN = 1, NTRAN
348*
349*                    Do for op(A) = A, A**T, or A**H.
350*
351                        TRANS = TRANSS( ITRAN )
352                        IF( ITRAN.EQ.1 ) THEN
353                           NORM = 'O'
354                           RCONDC = RCONDO
355                        ELSE
356                           NORM = 'I'
357                           RCONDC = RCONDI
358                        END IF
359*
360*+    TEST 1
361*                    Solve and compute residual for op(A)*x = b.
362*
363                        SRNAMT = 'SLARHS'
364                        CALL SLARHS( PATH, XTYPE, UPLO, TRANS, N, N, KD,
365     $                               IDIAG, NRHS, AB, LDAB, XACT, LDA,
366     $                               B, LDA, ISEED, INFO )
367                        XTYPE = 'C'
368                        CALL SLACPY( 'Full', N, NRHS, B, LDA, X, LDA )
369*
370                        SRNAMT = 'STBTRS'
371                        CALL STBTRS( UPLO, TRANS, DIAG, N, KD, NRHS, AB,
372     $                               LDAB, X, LDA, INFO )
373*
374*                    Check error code from STBTRS.
375*
376                        IF( INFO.NE.0 )
377     $                     CALL ALAERH( PATH, 'STBTRS', INFO, 0,
378     $                                  UPLO // TRANS // DIAG, N, N, KD,
379     $                                  KD, NRHS, IMAT, NFAIL, NERRS,
380     $                                  NOUT )
381*
382                        CALL STBT02( UPLO, TRANS, DIAG, N, KD, NRHS, AB,
383     $                               LDAB, X, LDA, B, LDA, WORK,
384     $                               RESULT( 1 ) )
385*
386*+    TEST 2
387*                    Check solution from generated exact solution.
388*
389                        CALL SGET04( N, NRHS, X, LDA, XACT, LDA, RCONDC,
390     $                               RESULT( 2 ) )
391*
392*+    TESTS 3, 4, and 5
393*                    Use iterative refinement to improve the solution
394*                    and compute error bounds.
395*
396                        SRNAMT = 'STBRFS'
397                        CALL STBRFS( UPLO, TRANS, DIAG, N, KD, NRHS, AB,
398     $                               LDAB, B, LDA, X, LDA, RWORK,
399     $                               RWORK( NRHS+1 ), WORK, IWORK,
400     $                               INFO )
401*
402*                    Check error code from STBRFS.
403*
404                        IF( INFO.NE.0 )
405     $                     CALL ALAERH( PATH, 'STBRFS', INFO, 0,
406     $                                  UPLO // TRANS // DIAG, N, N, KD,
407     $                                  KD, NRHS, IMAT, NFAIL, NERRS,
408     $                                  NOUT )
409*
410                        CALL SGET04( N, NRHS, X, LDA, XACT, LDA, RCONDC,
411     $                               RESULT( 3 ) )
412                        CALL STBT05( UPLO, TRANS, DIAG, N, KD, NRHS, AB,
413     $                               LDAB, B, LDA, X, LDA, XACT, LDA,
414     $                               RWORK, RWORK( NRHS+1 ),
415     $                               RESULT( 4 ) )
416*
417*                       Print information about the tests that did not
418*                       pass the threshold.
419*
420                        DO 40 K = 1, 5
421                           IF( RESULT( K ).GE.THRESH ) THEN
422                              IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
423     $                           CALL ALAHD( NOUT, PATH )
424                              WRITE( NOUT, FMT = 9999 )UPLO, TRANS,
425     $                           DIAG, N, KD, NRHS, IMAT, K, RESULT( K )
426                              NFAIL = NFAIL + 1
427                           END IF
428   40                   CONTINUE
429                        NRUN = NRUN + 5
430   50                CONTINUE
431   60             CONTINUE
432*
433*+    TEST 6
434*                    Get an estimate of RCOND = 1/CNDNUM.
435*
436                  DO 70 ITRAN = 1, 2
437                     IF( ITRAN.EQ.1 ) THEN
438                        NORM = 'O'
439                        RCONDC = RCONDO
440                     ELSE
441                        NORM = 'I'
442                        RCONDC = RCONDI
443                     END IF
444                     SRNAMT = 'STBCON'
445                     CALL STBCON( NORM, UPLO, DIAG, N, KD, AB, LDAB,
446     $                            RCOND, WORK, IWORK, INFO )
447*
448*                    Check error code from STBCON.
449*
450                     IF( INFO.NE.0 )
451     $                  CALL ALAERH( PATH, 'STBCON', INFO, 0,
452     $                               NORM // UPLO // DIAG, N, N, KD, KD,
453     $                               -1, IMAT, NFAIL, NERRS, NOUT )
454*
455                     CALL STBT06( RCOND, RCONDC, UPLO, DIAG, N, KD, AB,
456     $                            LDAB, RWORK, RESULT( 6 ) )
457*
458*                    Print information about the tests that did not pass
459*                    the threshold.
460*
461                     IF( RESULT( 6 ).GE.THRESH ) THEN
462                        IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
463     $                     CALL ALAHD( NOUT, PATH )
464                        WRITE( NOUT, FMT = 9998 ) 'STBCON', NORM, UPLO,
465     $                     DIAG, N, KD, IMAT, 6, RESULT( 6 )
466                        NFAIL = NFAIL + 1
467                     END IF
468                     NRUN = NRUN + 1
469   70             CONTINUE
470   80          CONTINUE
471   90       CONTINUE
472*
473*           Use pathological test matrices to test SLATBS.
474*
475            DO 120 IMAT = NTYPE1 + 1, NIMAT2
476*
477*              Do the tests only if DOTYPE( IMAT ) is true.
478*
479               IF( .NOT.DOTYPE( IMAT ) )
480     $            GO TO 120
481*
482               DO 110 IUPLO = 1, 2
483*
484*                 Do first for UPLO = 'U', then for UPLO = 'L'
485*
486                  UPLO = UPLOS( IUPLO )
487                  DO 100 ITRAN = 1, NTRAN
488*
489*                    Do for op(A) = A, A**T, and A**H.
490*
491                     TRANS = TRANSS( ITRAN )
492*
493*                    Call SLATTB to generate a triangular test matrix.
494*
495                     SRNAMT = 'SLATTB'
496                     CALL SLATTB( IMAT, UPLO, TRANS, DIAG, ISEED, N, KD,
497     $                            AB, LDAB, X, WORK, INFO )
498*
499*+    TEST 7
500*                    Solve the system op(A)*x = b
501*
502                     SRNAMT = 'SLATBS'
503                     CALL SCOPY( N, X, 1, B, 1 )
504                     CALL SLATBS( UPLO, TRANS, DIAG, 'N', N, KD, AB,
505     $                            LDAB, B, SCALE, RWORK, INFO )
506*
507*                    Check error code from SLATBS.
508*
509                     IF( INFO.NE.0 )
510     $                  CALL ALAERH( PATH, 'SLATBS', INFO, 0,
511     $                               UPLO // TRANS // DIAG // 'N', N, N,
512     $                               KD, KD, -1, IMAT, NFAIL, NERRS,
513     $                               NOUT )
514*
515                     CALL STBT03( UPLO, TRANS, DIAG, N, KD, 1, AB, LDAB,
516     $                            SCALE, RWORK, ONE, B, LDA, X, LDA,
517     $                            WORK, RESULT( 7 ) )
518*
519*+    TEST 8
520*                    Solve op(A)*x = b again with NORMIN = 'Y'.
521*
522                     CALL SCOPY( N, X, 1, B, 1 )
523                     CALL SLATBS( UPLO, TRANS, DIAG, 'Y', N, KD, AB,
524     $                            LDAB, B, SCALE, RWORK, INFO )
525*
526*                    Check error code from SLATBS.
527*
528                     IF( INFO.NE.0 )
529     $                  CALL ALAERH( PATH, 'SLATBS', INFO, 0,
530     $                               UPLO // TRANS // DIAG // 'Y', N, N,
531     $                               KD, KD, -1, IMAT, NFAIL, NERRS,
532     $                               NOUT )
533*
534                     CALL STBT03( UPLO, TRANS, DIAG, N, KD, 1, AB, LDAB,
535     $                            SCALE, RWORK, ONE, B, LDA, X, LDA,
536     $                            WORK, RESULT( 8 ) )
537*
538*                    Print information about the tests that did not pass
539*                    the threshold.
540*
541                     IF( RESULT( 7 ).GE.THRESH ) THEN
542                        IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
543     $                     CALL ALAHD( NOUT, PATH )
544                        WRITE( NOUT, FMT = 9997 )'SLATBS', UPLO, TRANS,
545     $                     DIAG, 'N', N, KD, IMAT, 7, RESULT( 7 )
546                        NFAIL = NFAIL + 1
547                     END IF
548                     IF( RESULT( 8 ).GE.THRESH ) THEN
549                        IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
550     $                     CALL ALAHD( NOUT, PATH )
551                        WRITE( NOUT, FMT = 9997 )'SLATBS', UPLO, TRANS,
552     $                     DIAG, 'Y', N, KD, IMAT, 8, RESULT( 8 )
553                        NFAIL = NFAIL + 1
554                     END IF
555                     NRUN = NRUN + 2
556  100             CONTINUE
557  110          CONTINUE
558  120       CONTINUE
559  130    CONTINUE
560  140 CONTINUE
561*
562*     Print a summary of the results.
563*
564      CALL ALASUM( PATH, NOUT, NFAIL, NRUN, NERRS )
565*
566 9999 FORMAT( ' UPLO=''', A1, ''', TRANS=''', A1, ''',
567     $      DIAG=''', A1, ''', N=', I5, ', KD=', I5, ', NRHS=', I5,
568     $      ', type ', I2, ', test(', I2, ')=', G12.5 )
569 9998 FORMAT( 1X, A, '( ''', A1, ''', ''', A1, ''', ''', A1, ''',',
570     $      I5, ',', I5, ',  ... ), type ', I2, ', test(', I2, ')=',
571     $      G12.5 )
572 9997 FORMAT( 1X, A, '( ''', A1, ''', ''', A1, ''', ''', A1, ''', ''',
573     $      A1, ''',', I5, ',', I5, ', ...  ),  type ', I2, ', test(',
574     $      I1, ')=', G12.5 )
575      RETURN
576*
577*     End of SCHKTB
578*
579      END
580