1       SUBROUTINE DDRVLS( DOTYPE, NM, MVAL, NN, NVAL, NNS, NSVAL, NNB,
  2      $                   NBVAL, NXVAL, THRESH, TSTERR, A, COPYA, B,
  3      $                   COPYB, C, S, COPYS, WORK, IWORK, NOUT )
  4 *
  5 *  -- LAPACK test routine (version 3.1.1) --
  6 *     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
  7 *     January 2007
  8 *
  9 *     .. Scalar Arguments ..
 10       LOGICAL            TSTERR
 11       INTEGER            NM, NN, NNB, NNS, NOUT
 12       DOUBLE PRECISION   THRESH
 13 *     ..
 14 *     .. Array Arguments ..
 15       LOGICAL            DOTYPE( * )
 16       INTEGER            IWORK( * ), MVAL( * ), NBVAL( * ), NSVAL( * ),
 17      $                   NVAL( * ), NXVAL( * )
 18       DOUBLE PRECISION   A( * ), B( * ), C( * ), COPYA( * ), COPYB( * ),
 19      $                   COPYS( * ), S( * ), WORK( * )
 20 *     ..
 21 *
 22 *  Purpose
 23 *  =======
 24 *
 25 *  DDRVLS tests the least squares driver routines DGELS, DGELSS, DGELSX,
 26 *  DGELSY and DGELSD.
 27 *
 28 *  Arguments
 29 *  =========
 30 *
 31 *  DOTYPE  (input) LOGICAL array, dimension (NTYPES)
 32 *          The matrix types to be used for testing.  Matrices of type j
 33 *          (for 1 <= j <= NTYPES) are used for testing if DOTYPE(j) =
 34 *          .TRUE.; if DOTYPE(j) = .FALSE., then type j is not used.
 35 *          The matrix of type j is generated as follows:
 36 *          j=1: A = U*D*V where U and V are random orthogonal matrices
 37 *               and D has random entries (> 0.1) taken from a uniform 
 38 *               distribution (0,1). A is full rank.
 39 *          j=2: The same of 1, but A is scaled up.
 40 *          j=3: The same of 1, but A is scaled down.
 41 *          j=4: A = U*D*V where U and V are random orthogonal matrices
 42 *               and D has 3*min(M,N)/4 random entries (> 0.1) taken
 43 *               from a uniform distribution (0,1) and the remaining
 44 *               entries set to 0. A is rank-deficient. 
 45 *          j=5: The same of 4, but A is scaled up.
 46 *          j=6: The same of 5, but A is scaled down.
 47 *
 48 *  NM      (input) INTEGER
 49 *          The number of values of M contained in the vector MVAL.
 50 *
 51 *  MVAL    (input) INTEGER array, dimension (NM)
 52 *          The values of the matrix row dimension M.
 53 *
 54 *  NN      (input) INTEGER
 55 *          The number of values of N contained in the vector NVAL.
 56 *
 57 *  NVAL    (input) INTEGER array, dimension (NN)
 58 *          The values of the matrix column dimension N.
 59 *
 60 *  NNS     (input) INTEGER
 61 *          The number of values of NRHS contained in the vector NSVAL.
 62 *
 63 *  NSVAL   (input) INTEGER array, dimension (NNS)
 64 *          The values of the number of right hand sides NRHS.
 65 *
 66 *  NNB     (input) INTEGER
 67 *          The number of values of NB and NX contained in the
 68 *          vectors NBVAL and NXVAL.  The blocking parameters are used
 69 *          in pairs (NB,NX).
 70 *
 71 *  NBVAL   (input) INTEGER array, dimension (NNB)
 72 *          The values of the blocksize NB.
 73 *
 74 *  NXVAL   (input) INTEGER array, dimension (NNB)
 75 *          The values of the crossover point NX.
 76 *
 77 *  THRESH  (input) DOUBLE PRECISION
 78 *          The threshold value for the test ratios.  A result is
 79 *          included in the output file if RESULT >= THRESH.  To have
 80 *          every test ratio printed, use THRESH = 0.
 81 *
 82 *  TSTERR  (input) LOGICAL
 83 *          Flag that indicates whether error exits are to be tested.
 84 *
 85 *  A       (workspace) DOUBLE PRECISION array, dimension (MMAX*NMAX)
 86 *          where MMAX is the maximum value of M in MVAL and NMAX is the
 87 *          maximum value of N in NVAL.
 88 *
 89 *  COPYA   (workspace) DOUBLE PRECISION array, dimension (MMAX*NMAX)
 90 *
 91 *  B       (workspace) DOUBLE PRECISION array, dimension (MMAX*NSMAX)
 92 *          where MMAX is the maximum value of M in MVAL and NSMAX is the
 93 *          maximum value of NRHS in NSVAL.
 94 *
 95 *  COPYB   (workspace) DOUBLE PRECISION array, dimension (MMAX*NSMAX)
 96 *
 97 *  C       (workspace) DOUBLE PRECISION array, dimension (MMAX*NSMAX)
 98 *
 99 *  S       (workspace) DOUBLE PRECISION array, dimension
100 *                      (min(MMAX,NMAX))
101 *
102 *  COPYS   (workspace) DOUBLE PRECISION array, dimension
103 *                      (min(MMAX,NMAX))
104 *
105 *  WORK    (workspace) DOUBLE PRECISION array,
106 *                      dimension (MMAX*NMAX + 4*NMAX + MMAX).
107 *
108 *  IWORK   (workspace) INTEGER array, dimension (15*NMAX)
109 *
110 *  NOUT    (input) INTEGER
111 *          The unit number for output.
112 *
113 *  =====================================================================
114 *
115 *     .. Parameters ..
116       INTEGER            NTESTS
117       PARAMETER          ( NTESTS = 18 )
118       INTEGER            SMLSIZ
119       PARAMETER          ( SMLSIZ = 25 )
120       DOUBLE PRECISION   ONE, TWO, ZERO
121       PARAMETER          ( ONE = 1.0D0, TWO = 2.0D0, ZERO = 0.0D0 )
122 *     ..
123 *     .. Local Scalars ..
124       CHARACTER          TRANS
125       CHARACTER*3        PATH
126       INTEGER            CRANK, I, IM, IN, INB, INFO, INS, IRANK, 
127      $                   ISCALE, ITRAN, ITYPE, J, K, LDA, LDB, LDWORK, 
128      $                   LWLSY, LWORK, M, MNMIN, N, NB, NCOLS, NERRS, 
129      $                   NFAIL, NLVL, NRHS, NROWS, NRUN, RANK
130       DOUBLE PRECISION   EPS, NORMA, NORMB, RCOND
131 *     ..
132 *     .. Local Arrays ..
133       INTEGER            ISEED( 4 ), ISEEDY( 4 )
134       DOUBLE PRECISION   RESULT( NTESTS )
135 *     ..
136 *     .. External Functions ..
137       DOUBLE PRECISION   DASUM, DLAMCH, DQRT12, DQRT14, DQRT17
138       EXTERNAL           DASUM, DLAMCH, DQRT12, DQRT14, DQRT17
139 *     ..
140 *     .. External Subroutines ..
141       EXTERNAL           ALAERH, ALAHD, ALASVM, DAXPY, DERRLS, DGELS,
142      $                   DGELSD, DGELSS, DGELSX, DGELSY, DGEMM, DLACPY,
143      $                   DLARNV, DLASRT, DQRT13, DQRT15, DQRT16, DSCAL,
144      $                   XLAENV
145 *     ..
146 *     .. Intrinsic Functions ..
147       INTRINSIC          DBLEINTLOGMAXMINSQRT
148 *     ..
149 *     .. Scalars in Common ..
150       LOGICAL            LERR, OK
151       CHARACTER*32       SRNAMT
152       INTEGER            INFOT, IOUNIT
153 *     ..
154 *     .. Common blocks ..
155       COMMON             / INFOC / INFOT, IOUNIT, OK, LERR
156       COMMON             / SRNAMC / SRNAMT
157 *     ..
158 *     .. Data statements ..
159       DATA               ISEEDY / 1988198919901991 /
160 *     ..
161 *     .. Executable Statements ..
162 *
163 *     Initialize constants and the random number seed.
164 *
165       PATH( 11 ) = 'Double precision'
166       PATH( 23 ) = 'LS'
167       NRUN = 0
168       NFAIL = 0
169       NERRS = 0
170       DO 10 I = 14
171          ISEED( I ) = ISEEDY( I )
172    10 CONTINUE
173       EPS = DLAMCH( 'Epsilon' )
174 *
175 *     Threshold for rank estimation
176 *
177       RCOND = SQRT( EPS ) - ( SQRT( EPS )-EPS ) / 2
178 *
179 *     Test the error exits
180 *
181       CALL XLAENV( 22 )
182       CALL XLAENV( 9, SMLSIZ )
183       IF( TSTERR )
184      $   CALL DERRLS( PATH, NOUT )
185 *
186 *     Print the header if NM = 0 or NN = 0 and THRESH = 0.
187 *
188       IF( ( NM.EQ.0 .OR. NN.EQ.0 ) .AND. THRESH.EQ.ZERO )
189      $   CALL ALAHD( NOUT, PATH )
190       INFOT = 0
191       CALL XLAENV( 22 )
192       CALL XLAENV( 9, SMLSIZ )
193 *
194       DO 150 IM = 1, NM
195          M = MVAL( IM )
196          LDA = MAX1, M )
197 *
198          DO 140 IN = 1, NN
199             N = NVAL( IN )
200             MNMIN = MIN( M, N )
201             LDB = MAX1, M, N )
202 *
203             DO 130 INS = 1, NNS
204                NRHS = NSVAL( INS )
205                NLVL = MAXINTLOGMAX( ONE, DBLE( MNMIN ) ) /
206      $                DBLE( SMLSIZ+1 ) ) / LOG( TWO ) ) + 10 )
207                LWORK = MAX1, ( M+NRHS )*( N+2 ), ( N+NRHS )*( M+2 ),
208      $                 M*N+4*MNMIN+MAX( M, N ), 12*MNMIN+2*MNMIN*SMLSIZ+
209      $                 8*MNMIN*NLVL+MNMIN*NRHS+(SMLSIZ+1)**2 )
210 *
211                DO 120 IRANK = 12
212                   DO 110 ISCALE = 13
213                      ITYPE = ( IRANK-1 )*3 + ISCALE
214                      IF.NOT.DOTYPE( ITYPE ) )
215      $                  GO TO 110
216 *
217                      IF( IRANK.EQ.1 ) THEN
218 *
219 *                       Test DGELS
220 *
221 *                       Generate a matrix of scaling type ISCALE
222 *
223                         CALL DQRT13( ISCALE, M, N, COPYA, LDA, NORMA,
224      $                               ISEED )
225                         DO 40 INB = 1, NNB
226                            NB = NBVAL( INB )
227                            CALL XLAENV( 1, NB )
228                            CALL XLAENV( 3, NXVAL( INB ) )
229 *
230                            DO 30 ITRAN = 12
231                               IF( ITRAN.EQ.1 ) THEN
232                                  TRANS = 'N'
233                                  NROWS = M
234                                  NCOLS = N
235                               ELSE
236                                  TRANS = 'T'
237                                  NROWS = N
238                                  NCOLS = M
239                               END IF
240                               LDWORK = MAX1, NCOLS )
241 *
242 *                             Set up a consistent rhs
243 *
244                               IF( NCOLS.GT.0 ) THEN
245                                  CALL DLARNV( 2, ISEED, NCOLS*NRHS,
246      $                                        WORK )
247                                  CALL DSCAL( NCOLS*NRHS,
248      $                                       ONE / DBLE( NCOLS ), WORK,
249      $                                       1 )
250                               END IF
251                               CALL DGEMM( TRANS, 'No transpose', NROWS,
252      $                                    NRHS, NCOLS, ONE, COPYA, LDA,
253      $                                    WORK, LDWORK, ZERO, B, LDB )
254                               CALL DLACPY( 'Full', NROWS, NRHS, B, LDB,
255      $                                     COPYB, LDB )
256 *
257 *                             Solve LS or overdetermined system
258 *
259                               IF( M.GT.0 .AND. N.GT.0 ) THEN
260                                  CALL DLACPY( 'Full', M, N, COPYA, LDA,
261      $                                        A, LDA )
262                                  CALL DLACPY( 'Full', NROWS, NRHS,
263      $                                        COPYB, LDB, B, LDB )
264                               END IF
265                               SRNAMT = 'DGELS '
266                               CALL DGELS( TRANS, M, N, NRHS, A, LDA, B,
267      $                                    LDB, WORK, LWORK, INFO )
268                               IF( INFO.NE.0 )
269      $                           CALL ALAERH( PATH, 'DGELS ', INFO, 0,
270      $                                        TRANS, M, N, NRHS, -1, NB,
271      $                                        ITYPE, NFAIL, NERRS,
272      $                                        NOUT )
273 *
274 *                             Check correctness of results
275 *
276                               LDWORK = MAX1, NROWS )
277                               IF( NROWS.GT.0 .AND. NRHS.GT.0 )
278      $                           CALL DLACPY( 'Full', NROWS, NRHS,
279      $                                        COPYB, LDB, C, LDB )
280                               CALL DQRT16( TRANS, M, N, NRHS, COPYA,
281      $                                     LDA, B, LDB, C, LDB, WORK,
282      $                                     RESULT1 ) )
283 *
284                               IF( ( ITRAN.EQ.1 .AND. M.GE.N ) .OR.
285      $                            ( ITRAN.EQ.2 .AND. M.LT.N ) ) THEN
286 *
287 *                                Solving LS system
288 *
289                                  RESULT2 ) = DQRT17( TRANS, 1, M, N,
290      $                                         NRHS, COPYA, LDA, B, LDB,
291      $                                         COPYB, LDB, C, WORK,
292      $                                         LWORK )
293                               ELSE
294 *
295 *                                Solving overdetermined system
296 *
297                                  RESULT2 ) = DQRT14( TRANS, M, N,
298      $                                         NRHS, COPYA, LDA, B, LDB,
299      $                                         WORK, LWORK )
300                               END IF
301 *
302 *                             Print information about the tests that
303 *                             did not pass the threshold.
304 *
305                               DO 20 K = 12
306                                  IFRESULT( K ).GE.THRESH ) THEN
307                                     IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
308      $                                 CALL ALAHD( NOUT, PATH )
309                                     WRITE( NOUT, FMT = 9999 )TRANS, M,
310      $                                 N, NRHS, NB, ITYPE, K,
311      $                                 RESULT( K )
312                                     NFAIL = NFAIL + 1
313                                  END IF
314    20                         CONTINUE
315                               NRUN = NRUN + 2
316    30                      CONTINUE
317    40                   CONTINUE
318                      END IF
319 *
320 *                    Generate a matrix of scaling type ISCALE and rank
321 *                    type IRANK.
322 *
323                      CALL DQRT15( ISCALE, IRANK, M, N, NRHS, COPYA, LDA,
324      $                            COPYB, LDB, COPYS, RANK, NORMA, NORMB,
325      $                            ISEED, WORK, LWORK )
326 *
327 *                    workspace used: MAX(M+MIN(M,N),NRHS*MIN(M,N),2*N+M)
328 *
329 *                    Initialize vector IWORK.
330 *
331                      DO 50 J = 1, N
332                         IWORK( J ) = 0
333    50                CONTINUE
334                      LDWORK = MAX1, M )
335 *
336 *                    Test DGELSX
337 *
338 *                    DGELSX:  Compute the minimum-norm solution X
339 *                    to min( norm( A * X - B ) ) using a complete
340 *                    orthogonal factorization.
341 *
342                      CALL DLACPY( 'Full', M, N, COPYA, LDA, A, LDA )
343                      CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, B, LDB )
344 *
345                      SRNAMT = 'DGELSX'
346                      CALL DGELSX( M, N, NRHS, A, LDA, B, LDB, IWORK,
347      $                            RCOND, CRANK, WORK, INFO )
348                      IF( INFO.NE.0 )
349      $                  CALL ALAERH( PATH, 'DGELSX', INFO, 0' ', M, N,
350      $                               NRHS, -1, NB, ITYPE, NFAIL, NERRS,
351      $                               NOUT )
352 *
353 *                    workspace used: MAX( MNMIN+3*N, 2*MNMIN+NRHS )
354 *
355 *                    Test 3:  Compute relative error in svd
356 *                             workspace: M*N + 4*MIN(M,N) + MAX(M,N)
357 *
358                      RESULT3 ) = DQRT12( CRANK, CRANK, A, LDA, COPYS,
359      $                             WORK, LWORK )
360 *
361 *                    Test 4:  Compute error in solution
362 *                             workspace:  M*NRHS + M
363 *
364                      CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, WORK,
365      $                            LDWORK )
366                      CALL DQRT16( 'No transpose', M, N, NRHS, COPYA,
367      $                            LDA, B, LDB, WORK, LDWORK,
368      $                            WORK( M*NRHS+1 ), RESULT4 ) )
369 *
370 *                    Test 5:  Check norm of r'*A
371 *                             workspace: NRHS*(M+N)
372 *
373                      RESULT5 ) = ZERO
374                      IF( M.GT.CRANK )
375      $                  RESULT5 ) = DQRT17( 'No transpose'1, M, N,
376      $                                NRHS, COPYA, LDA, B, LDB, COPYB,
377      $                                LDB, C, WORK, LWORK )
378 *
379 *                    Test 6:  Check if x is in the rowspace of A
380 *                             workspace: (M+NRHS)*(N+2)
381 *
382                      RESULT6 ) = ZERO
383 *
384                      IF( N.GT.CRANK )
385      $                  RESULT6 ) = DQRT14( 'No transpose', M, N,
386      $                                NRHS, COPYA, LDA, B, LDB, WORK,
387      $                                LWORK )
388 *
389 *                    Print information about the tests that did not
390 *                    pass the threshold.
391 *
392                      DO 60 K = 36
393                         IFRESULT( K ).GE.THRESH ) THEN
394                            IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
395      $                        CALL ALAHD( NOUT, PATH )
396                            WRITE( NOUT, FMT = 9998 )M, N, NRHS, NB,
397      $                        ITYPE, K, RESULT( K )
398                            NFAIL = NFAIL + 1
399                         END IF
400    60                CONTINUE
401                      NRUN = NRUN + 4
402 *
403 *                    Loop for testing different block sizes.
404 *
405                      DO 100 INB = 1, NNB
406                         NB = NBVAL( INB )
407                         CALL XLAENV( 1, NB )
408                         CALL XLAENV( 3, NXVAL( INB ) )
409 *
410 *                       Test DGELSY
411 *
412 *                       DGELSY:  Compute the minimum-norm solution X
413 *                       to min( norm( A * X - B ) )
414 *                       using the rank-revealing orthogonal
415 *                       factorization.
416 *
417 *                       Initialize vector IWORK.
418 *
419                         DO 70 J = 1, N
420                            IWORK( J ) = 0
421    70                   CONTINUE
422 *
423 *                       Set LWLSY to the adequate value.
424 *
425                         LWLSY = MAX1, MNMIN+2*N+NB*( N+1 ),
426      $                          2*MNMIN+NB*NRHS )
427 *
428                         CALL DLACPY( 'Full', M, N, COPYA, LDA, A, LDA )
429                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, B,
430      $                               LDB )
431 *
432                         SRNAMT = 'DGELSY'
433                         CALL DGELSY( M, N, NRHS, A, LDA, B, LDB, IWORK,
434      $                               RCOND, CRANK, WORK, LWLSY, INFO )
435                         IF( INFO.NE.0 )
436      $                     CALL ALAERH( PATH, 'DGELSY', INFO, 0' ', M,
437      $                                  N, NRHS, -1, NB, ITYPE, NFAIL,
438      $                                  NERRS, NOUT )
439 *
440 *                       Test 7:  Compute relative error in svd
441 *                                workspace: M*N + 4*MIN(M,N) + MAX(M,N)
442 *
443                         RESULT7 ) = DQRT12( CRANK, CRANK, A, LDA,
444      $                                COPYS, WORK, LWORK )
445 *
446 *                       Test 8:  Compute error in solution
447 *                                workspace:  M*NRHS + M
448 *
449                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, WORK,
450      $                               LDWORK )
451                         CALL DQRT16( 'No transpose', M, N, NRHS, COPYA,
452      $                               LDA, B, LDB, WORK, LDWORK,
453      $                               WORK( M*NRHS+1 ), RESULT8 ) )
454 *
455 *                       Test 9:  Check norm of r'*A
456 *                                workspace: NRHS*(M+N)
457 *
458                         RESULT9 ) = ZERO
459                         IF( M.GT.CRANK )
460      $                     RESULT9 ) = DQRT17( 'No transpose'1, M,
461      $                                   N, NRHS, COPYA, LDA, B, LDB,
462      $                                   COPYB, LDB, C, WORK, LWORK )
463 *
464 *                       Test 10:  Check if x is in the rowspace of A
465 *                                workspace: (M+NRHS)*(N+2)
466 *
467                         RESULT10 ) = ZERO
468 *
469                         IF( N.GT.CRANK )
470      $                     RESULT10 ) = DQRT14( 'No transpose', M, N,
471      $                                    NRHS, COPYA, LDA, B, LDB,
472      $                                    WORK, LWORK )
473 *
474 *                       Test DGELSS
475 *
476 *                       DGELSS:  Compute the minimum-norm solution X
477 *                       to min( norm( A * X - B ) )
478 *                       using the SVD.
479 *
480                         CALL DLACPY( 'Full', M, N, COPYA, LDA, A, LDA )
481                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, B,
482      $                               LDB )
483                         SRNAMT = 'DGELSS'
484                         CALL DGELSS( M, N, NRHS, A, LDA, B, LDB, S,
485      $                               RCOND, CRANK, WORK, LWORK, INFO )
486                         IF( INFO.NE.0 )
487      $                     CALL ALAERH( PATH, 'DGELSS', INFO, 0' ', M,
488      $                                  N, NRHS, -1, NB, ITYPE, NFAIL,
489      $                                  NERRS, NOUT )
490 *
491 *                       workspace used: 3*min(m,n) +
492 *                                       max(2*min(m,n),nrhs,max(m,n))
493 *
494 *                       Test 11:  Compute relative error in svd
495 *
496                         IF( RANK.GT.0 ) THEN
497                            CALL DAXPY( MNMIN, -ONE, COPYS, 1, S, 1 )
498                            RESULT11 ) = DASUM( MNMIN, S, 1 ) /
499      $                                    DASUM( MNMIN, COPYS, 1 ) /
500      $                                    ( EPS*DBLE( MNMIN ) )
501                         ELSE
502                            RESULT11 ) = ZERO
503                         END IF
504 *
505 *                       Test 12:  Compute error in solution
506 *
507                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, WORK,
508      $                               LDWORK )
509                         CALL DQRT16( 'No transpose', M, N, NRHS, COPYA,
510      $                               LDA, B, LDB, WORK, LDWORK,
511      $                               WORK( M*NRHS+1 ), RESULT12 ) )
512 *
513 *                       Test 13:  Check norm of r'*A
514 *
515                         RESULT13 ) = ZERO
516                         IF( M.GT.CRANK )
517      $                     RESULT13 ) = DQRT17( 'No transpose'1, M,
518      $                                    N, NRHS, COPYA, LDA, B, LDB,
519      $                                    COPYB, LDB, C, WORK, LWORK )
520 *
521 *                       Test 14:  Check if x is in the rowspace of A
522 *
523                         RESULT14 ) = ZERO
524                         IF( N.GT.CRANK )
525      $                     RESULT14 ) = DQRT14( 'No transpose', M, N,
526      $                                    NRHS, COPYA, LDA, B, LDB,
527      $                                    WORK, LWORK )
528 *
529 *                       Test DGELSD
530 *
531 *                       DGELSD:  Compute the minimum-norm solution X
532 *                       to min( norm( A * X - B ) ) using a
533 *                       divide and conquer SVD.
534 *
535 *                       Initialize vector IWORK.
536 *
537                         DO 80 J = 1, N
538                            IWORK( J ) = 0
539    80                   CONTINUE
540 *
541                         CALL DLACPY( 'Full', M, N, COPYA, LDA, A, LDA )
542                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, B,
543      $                               LDB )
544 *
545                         SRNAMT = 'DGELSD'
546                         CALL DGELSD( M, N, NRHS, A, LDA, B, LDB, S,
547      $                               RCOND, CRANK, WORK, LWORK, IWORK,
548      $                               INFO )
549                         IF( INFO.NE.0 )
550      $                     CALL ALAERH( PATH, 'DGELSD', INFO, 0' ', M,
551      $                                  N, NRHS, -1, NB, ITYPE, NFAIL,
552      $                                  NERRS, NOUT )
553 *
554 *                       Test 15:  Compute relative error in svd
555 *
556                         IF( RANK.GT.0 ) THEN
557                            CALL DAXPY( MNMIN, -ONE, COPYS, 1, S, 1 )
558                            RESULT15 ) = DASUM( MNMIN, S, 1 ) /
559      $                                    DASUM( MNMIN, COPYS, 1 ) /
560      $                                    ( EPS*DBLE( MNMIN ) )
561                         ELSE
562                            RESULT15 ) = ZERO
563                         END IF
564 *
565 *                       Test 16:  Compute error in solution
566 *
567                         CALL DLACPY( 'Full', M, NRHS, COPYB, LDB, WORK,
568      $                               LDWORK )
569                         CALL DQRT16( 'No transpose', M, N, NRHS, COPYA,
570      $                               LDA, B, LDB, WORK, LDWORK,
571      $                               WORK( M*NRHS+1 ), RESULT16 ) )
572 *
573 *                       Test 17:  Check norm of r'*A
574 *
575                         RESULT17 ) = ZERO
576                         IF( M.GT.CRANK )
577      $                     RESULT17 ) = DQRT17( 'No transpose'1, M,
578      $                                    N, NRHS, COPYA, LDA, B, LDB,
579      $                                    COPYB, LDB, C, WORK, LWORK )
580 *
581 *                       Test 18:  Check if x is in the rowspace of A
582 *
583                         RESULT18 ) = ZERO
584                         IF( N.GT.CRANK )
585      $                     RESULT18 ) = DQRT14( 'No transpose', M, N,
586      $                                    NRHS, COPYA, LDA, B, LDB,
587      $                                    WORK, LWORK )
588 *
589 *                       Print information about the tests that did not
590 *                       pass the threshold.
591 *
592                         DO 90 K = 7, NTESTS
593                            IFRESULT( K ).GE.THRESH ) THEN
594                               IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
595      $                           CALL ALAHD( NOUT, PATH )
596                               WRITE( NOUT, FMT = 9998 )M, N, NRHS, NB,
597      $                           ITYPE, K, RESULT( K )
598                               NFAIL = NFAIL + 1
599                            END IF
600    90                   CONTINUE
601                         NRUN = NRUN + 12 
602 *
603   100                CONTINUE
604   110             CONTINUE
605   120          CONTINUE
606   130       CONTINUE
607   140    CONTINUE
608   150 CONTINUE
609 *
610 *     Print a summary of the results.
611 *
612       CALL ALASVM( PATH, NOUT, NFAIL, NRUN, NERRS )
613 *
614  9999 FORMAT' TRANS=''', A1, ''', M=', I5, ', N=', I5, ', NRHS=', I4,
615      $      ', NB=', I4, ', type', I2, ', test(', I2, ')='G12.5 )
616  9998 FORMAT' M=', I5, ', N=', I5, ', NRHS=', I4, ', NB=', I4,
617      $      ', type', I2, ', test(', I2, ')='G12.5 )
618       RETURN
619 *
620 *     End of DDRVLS
621 *
622       END