1*> \brief \b SCHKBD
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 SCHKBD( NSIZES, MVAL, NVAL, NTYPES, DOTYPE, NRHS,
12*                          ISEED, THRESH, A, LDA, BD, BE, S1, S2, X, LDX,
13*                          Y, Z, Q, LDQ, PT, LDPT, U, VT, WORK, LWORK,
14*                          IWORK, NOUT, INFO )
15*
16*       .. Scalar Arguments ..
17*       INTEGER            INFO, LDA, LDPT, LDQ, LDX, LWORK, NOUT, NRHS,
18*      $                   NSIZES, NTYPES
19*       REAL               THRESH
20*       ..
21*       .. Array Arguments ..
22*       LOGICAL            DOTYPE( * )
23*       INTEGER            ISEED( 4 ), IWORK( * ), MVAL( * ), NVAL( * )
24*       REAL               A( LDA, * ), BD( * ), BE( * ), PT( LDPT, * ),
25*      $                   Q( LDQ, * ), S1( * ), S2( * ), U( LDPT, * ),
26*      $                   VT( LDPT, * ), WORK( * ), X( LDX, * ),
27*      $                   Y( LDX, * ), Z( LDX, * )
28*       ..
29*
30*
31*> \par Purpose:
32*  =============
33*>
34*> \verbatim
35*>
36*> SCHKBD checks the singular value decomposition (SVD) routines.
37*>
38*> SGEBRD reduces a real general m by n matrix A to upper or lower
39*> bidiagonal form B by an orthogonal transformation:  Q' * A * P = B
40*> (or A = Q * B * P').  The matrix B is upper bidiagonal if m >= n
41*> and lower bidiagonal if m < n.
42*>
43*> SORGBR generates the orthogonal matrices Q and P' from SGEBRD.
44*> Note that Q and P are not necessarily square.
45*>
46*> SBDSQR computes the singular value decomposition of the bidiagonal
47*> matrix B as B = U S V'.  It is called three times to compute
48*>    1)  B = U S1 V', where S1 is the diagonal matrix of singular
49*>        values and the columns of the matrices U and V are the left
50*>        and right singular vectors, respectively, of B.
51*>    2)  Same as 1), but the singular values are stored in S2 and the
52*>        singular vectors are not computed.
53*>    3)  A = (UQ) S (P'V'), the SVD of the original matrix A.
54*> In addition, SBDSQR has an option to apply the left orthogonal matrix
55*> U to a matrix X, useful in least squares applications.
56*>
57*> SBDSDC computes the singular value decomposition of the bidiagonal
58*> matrix B as B = U S V' using divide-and-conquer. It is called twice
59*> to compute
60*>    1) B = U S1 V', where S1 is the diagonal matrix of singular
61*>        values and the columns of the matrices U and V are the left
62*>        and right singular vectors, respectively, of B.
63*>    2) Same as 1), but the singular values are stored in S2 and the
64*>        singular vectors are not computed.
65*>
66*> For each pair of matrix dimensions (M,N) and each selected matrix
67*> type, an M by N matrix A and an M by NRHS matrix X are generated.
68*> The problem dimensions are as follows
69*>    A:          M x N
70*>    Q:          M x min(M,N) (but M x M if NRHS > 0)
71*>    P:          min(M,N) x N
72*>    B:          min(M,N) x min(M,N)
73*>    U, V:       min(M,N) x min(M,N)
74*>    S1, S2      diagonal, order min(M,N)
75*>    X:          M x NRHS
76*>
77*> For each generated matrix, 14 tests are performed:
78*>
79*> Test SGEBRD and SORGBR
80*>
81*> (1)   | A - Q B PT | / ( |A| max(M,N) ulp ), PT = P'
82*>
83*> (2)   | I - Q' Q | / ( M ulp )
84*>
85*> (3)   | I - PT PT' | / ( N ulp )
86*>
87*> Test SBDSQR on bidiagonal matrix B
88*>
89*> (4)   | B - U S1 VT | / ( |B| min(M,N) ulp ), VT = V'
90*>
91*> (5)   | Y - U Z | / ( |Y| max(min(M,N),k) ulp ), where Y = Q' X
92*>                                                  and   Z = U' Y.
93*> (6)   | I - U' U | / ( min(M,N) ulp )
94*>
95*> (7)   | I - VT VT' | / ( min(M,N) ulp )
96*>
97*> (8)   S1 contains min(M,N) nonnegative values in decreasing order.
98*>       (Return 0 if true, 1/ULP if false.)
99*>
100*> (9)   | S1 - S2 | / ( |S1| ulp ), where S2 is computed without
101*>                                   computing U and V.
102*>
103*> (10)  0 if the true singular values of B are within THRESH of
104*>       those in S1.  2*THRESH if they are not.  (Tested using
105*>       SSVDCH)
106*>
107*> Test SBDSQR on matrix A
108*>
109*> (11)  | A - (QU) S (VT PT) | / ( |A| max(M,N) ulp )
110*>
111*> (12)  | X - (QU) Z | / ( |X| max(M,k) ulp )
112*>
113*> (13)  | I - (QU)'(QU) | / ( M ulp )
114*>
115*> (14)  | I - (VT PT) (PT'VT') | / ( N ulp )
116*>
117*> Test SBDSDC on bidiagonal matrix B
118*>
119*> (15)  | B - U S1 VT | / ( |B| min(M,N) ulp ), VT = V'
120*>
121*> (16)  | I - U' U | / ( min(M,N) ulp )
122*>
123*> (17)  | I - VT VT' | / ( min(M,N) ulp )
124*>
125*> (18)  S1 contains min(M,N) nonnegative values in decreasing order.
126*>       (Return 0 if true, 1/ULP if false.)
127*>
128*> (19)  | S1 - S2 | / ( |S1| ulp ), where S2 is computed without
129*>                                   computing U and V.
130*> The possible matrix types are
131*>
132*> (1)  The zero matrix.
133*> (2)  The identity matrix.
134*>
135*> (3)  A diagonal matrix with evenly spaced entries
136*>      1, ..., ULP  and random signs.
137*>      (ULP = (first number larger than 1) - 1 )
138*> (4)  A diagonal matrix with geometrically spaced entries
139*>      1, ..., ULP  and random signs.
140*> (5)  A diagonal matrix with "clustered" entries 1, ULP, ..., ULP
141*>      and random signs.
142*>
143*> (6)  Same as (3), but multiplied by SQRT( overflow threshold )
144*> (7)  Same as (3), but multiplied by SQRT( underflow threshold )
145*>
146*> (8)  A matrix of the form  U D V, where U and V are orthogonal and
147*>      D has evenly spaced entries 1, ..., ULP with random signs
148*>      on the diagonal.
149*>
150*> (9)  A matrix of the form  U D V, where U and V are orthogonal and
151*>      D has geometrically spaced entries 1, ..., ULP with random
152*>      signs on the diagonal.
153*>
154*> (10) A matrix of the form  U D V, where U and V are orthogonal and
155*>      D has "clustered" entries 1, ULP,..., ULP with random
156*>      signs on the diagonal.
157*>
158*> (11) Same as (8), but multiplied by SQRT( overflow threshold )
159*> (12) Same as (8), but multiplied by SQRT( underflow threshold )
160*>
161*> (13) Rectangular matrix with random entries chosen from (-1,1).
162*> (14) Same as (13), but multiplied by SQRT( overflow threshold )
163*> (15) Same as (13), but multiplied by SQRT( underflow threshold )
164*>
165*> Special case:
166*> (16) A bidiagonal matrix with random entries chosen from a
167*>      logarithmic distribution on [ulp^2,ulp^(-2)]  (I.e., each
168*>      entry is  e^x, where x is chosen uniformly on
169*>      [ 2 log(ulp), -2 log(ulp) ] .)  For *this* type:
170*>      (a) SGEBRD is not called to reduce it to bidiagonal form.
171*>      (b) the bidiagonal is  min(M,N) x min(M,N); if M<N, the
172*>          matrix will be lower bidiagonal, otherwise upper.
173*>      (c) only tests 5--8 and 14 are performed.
174*>
175*> A subset of the full set of matrix types may be selected through
176*> the logical array DOTYPE.
177*> \endverbatim
178*
179*  Arguments:
180*  ==========
181*
182*> \param[in] NSIZES
183*> \verbatim
184*>          NSIZES is INTEGER
185*>          The number of values of M and N contained in the vectors
186*>          MVAL and NVAL.  The matrix sizes are used in pairs (M,N).
187*> \endverbatim
188*>
189*> \param[in] MVAL
190*> \verbatim
191*>          MVAL is INTEGER array, dimension (NM)
192*>          The values of the matrix row dimension M.
193*> \endverbatim
194*>
195*> \param[in] NVAL
196*> \verbatim
197*>          NVAL is INTEGER array, dimension (NM)
198*>          The values of the matrix column dimension N.
199*> \endverbatim
200*>
201*> \param[in] NTYPES
202*> \verbatim
203*>          NTYPES is INTEGER
204*>          The number of elements in DOTYPE.   If it is zero, SCHKBD
205*>          does nothing.  It must be at least zero.  If it is MAXTYP+1
206*>          and NSIZES is 1, then an additional type, MAXTYP+1 is
207*>          defined, which is to use whatever matrices are in A and B.
208*>          This is only useful if DOTYPE(1:MAXTYP) is .FALSE. and
209*>          DOTYPE(MAXTYP+1) is .TRUE. .
210*> \endverbatim
211*>
212*> \param[in] DOTYPE
213*> \verbatim
214*>          DOTYPE is LOGICAL array, dimension (NTYPES)
215*>          If DOTYPE(j) is .TRUE., then for each size (m,n), a matrix
216*>          of type j will be generated.  If NTYPES is smaller than the
217*>          maximum number of types defined (PARAMETER MAXTYP), then
218*>          types NTYPES+1 through MAXTYP will not be generated.  If
219*>          NTYPES is larger than MAXTYP, DOTYPE(MAXTYP+1) through
220*>          DOTYPE(NTYPES) will be ignored.
221*> \endverbatim
222*>
223*> \param[in] NRHS
224*> \verbatim
225*>          NRHS is INTEGER
226*>          The number of columns in the "right-hand side" matrices X, Y,
227*>          and Z, used in testing SBDSQR.  If NRHS = 0, then the
228*>          operations on the right-hand side will not be tested.
229*>          NRHS must be at least 0.
230*> \endverbatim
231*>
232*> \param[in,out] ISEED
233*> \verbatim
234*>          ISEED is INTEGER array, dimension (4)
235*>          On entry ISEED specifies the seed of the random number
236*>          generator. The array elements should be between 0 and 4095;
237*>          if not they will be reduced mod 4096.  Also, ISEED(4) must
238*>          be odd.  The values of ISEED are changed on exit, and can be
239*>          used in the next call to SCHKBD to continue the same random
240*>          number sequence.
241*> \endverbatim
242*>
243*> \param[in] THRESH
244*> \verbatim
245*>          THRESH is REAL
246*>          The threshold value for the test ratios.  A result is
247*>          included in the output file if RESULT >= THRESH.  To have
248*>          every test ratio printed, use THRESH = 0.  Note that the
249*>          expected value of the test ratios is O(1), so THRESH should
250*>          be a reasonably small multiple of 1, e.g., 10 or 100.
251*> \endverbatim
252*>
253*> \param[out] A
254*> \verbatim
255*>          A is REAL array, dimension (LDA,NMAX)
256*>          where NMAX is the maximum value of N in NVAL.
257*> \endverbatim
258*>
259*> \param[in] LDA
260*> \verbatim
261*>          LDA is INTEGER
262*>          The leading dimension of the array A.  LDA >= max(1,MMAX),
263*>          where MMAX is the maximum value of M in MVAL.
264*> \endverbatim
265*>
266*> \param[out] BD
267*> \verbatim
268*>          BD is REAL array, dimension
269*>                      (max(min(MVAL(j),NVAL(j))))
270*> \endverbatim
271*>
272*> \param[out] BE
273*> \verbatim
274*>          BE is REAL array, dimension
275*>                      (max(min(MVAL(j),NVAL(j))))
276*> \endverbatim
277*>
278*> \param[out] S1
279*> \verbatim
280*>          S1 is REAL array, dimension
281*>                      (max(min(MVAL(j),NVAL(j))))
282*> \endverbatim
283*>
284*> \param[out] S2
285*> \verbatim
286*>          S2 is REAL array, dimension
287*>                      (max(min(MVAL(j),NVAL(j))))
288*> \endverbatim
289*>
290*> \param[out] X
291*> \verbatim
292*>          X is REAL array, dimension (LDX,NRHS)
293*> \endverbatim
294*>
295*> \param[in] LDX
296*> \verbatim
297*>          LDX is INTEGER
298*>          The leading dimension of the arrays X, Y, and Z.
299*>          LDX >= max(1,MMAX)
300*> \endverbatim
301*>
302*> \param[out] Y
303*> \verbatim
304*>          Y is REAL array, dimension (LDX,NRHS)
305*> \endverbatim
306*>
307*> \param[out] Z
308*> \verbatim
309*>          Z is REAL array, dimension (LDX,NRHS)
310*> \endverbatim
311*>
312*> \param[out] Q
313*> \verbatim
314*>          Q is REAL array, dimension (LDQ,MMAX)
315*> \endverbatim
316*>
317*> \param[in] LDQ
318*> \verbatim
319*>          LDQ is INTEGER
320*>          The leading dimension of the array Q.  LDQ >= max(1,MMAX).
321*> \endverbatim
322*>
323*> \param[out] PT
324*> \verbatim
325*>          PT is REAL array, dimension (LDPT,NMAX)
326*> \endverbatim
327*>
328*> \param[in] LDPT
329*> \verbatim
330*>          LDPT is INTEGER
331*>          The leading dimension of the arrays PT, U, and V.
332*>          LDPT >= max(1, max(min(MVAL(j),NVAL(j)))).
333*> \endverbatim
334*>
335*> \param[out] U
336*> \verbatim
337*>          U is REAL array, dimension
338*>                      (LDPT,max(min(MVAL(j),NVAL(j))))
339*> \endverbatim
340*>
341*> \param[out] VT
342*> \verbatim
343*>          VT is REAL array, dimension
344*>                      (LDPT,max(min(MVAL(j),NVAL(j))))
345*> \endverbatim
346*>
347*> \param[out] WORK
348*> \verbatim
349*>          WORK is REAL array, dimension (LWORK)
350*> \endverbatim
351*>
352*> \param[in] LWORK
353*> \verbatim
354*>          LWORK is INTEGER
355*>          The number of entries in WORK.  This must be at least
356*>          3(M+N) and  M(M + max(M,N,k) + 1) + N*min(M,N)  for all
357*>          pairs  (M,N)=(MM(j),NN(j))
358*> \endverbatim
359*>
360*> \param[out] IWORK
361*> \verbatim
362*>          IWORK is INTEGER array, dimension at least 8*min(M,N)
363*> \endverbatim
364*>
365*> \param[in] NOUT
366*> \verbatim
367*>          NOUT is INTEGER
368*>          The FORTRAN unit number for printing out error messages
369*>          (e.g., if a routine returns IINFO not equal to 0.)
370*> \endverbatim
371*>
372*> \param[out] INFO
373*> \verbatim
374*>          INFO is INTEGER
375*>          If 0, then everything ran OK.
376*>           -1: NSIZES < 0
377*>           -2: Some MM(j) < 0
378*>           -3: Some NN(j) < 0
379*>           -4: NTYPES < 0
380*>           -6: NRHS  < 0
381*>           -8: THRESH < 0
382*>          -11: LDA < 1 or LDA < MMAX, where MMAX is max( MM(j) ).
383*>          -17: LDB < 1 or LDB < MMAX.
384*>          -21: LDQ < 1 or LDQ < MMAX.
385*>          -23: LDPT< 1 or LDPT< MNMAX.
386*>          -27: LWORK too small.
387*>          If  SLATMR, SLATMS, SGEBRD, SORGBR, or SBDSQR,
388*>              returns an error code, the
389*>              absolute value of it is returned.
390*>
391*>-----------------------------------------------------------------------
392*>
393*>     Some Local Variables and Parameters:
394*>     ---- ----- --------- --- ----------
395*>
396*>     ZERO, ONE       Real 0 and 1.
397*>     MAXTYP          The number of types defined.
398*>     NTEST           The number of tests performed, or which can
399*>                     be performed so far, for the current matrix.
400*>     MMAX            Largest value in NN.
401*>     NMAX            Largest value in NN.
402*>     MNMIN           min(MM(j), NN(j)) (the dimension of the bidiagonal
403*>                     matrix.)
404*>     MNMAX           The maximum value of MNMIN for j=1,...,NSIZES.
405*>     NFAIL           The number of tests which have exceeded THRESH
406*>     COND, IMODE     Values to be passed to the matrix generators.
407*>     ANORM           Norm of A; passed to matrix generators.
408*>
409*>     OVFL, UNFL      Overflow and underflow thresholds.
410*>     RTOVFL, RTUNFL  Square roots of the previous 2 values.
411*>     ULP, ULPINV     Finest relative precision and its inverse.
412*>
413*>             The following four arrays decode JTYPE:
414*>     KTYPE(j)        The general type (1-10) for type "j".
415*>     KMODE(j)        The MODE value to be passed to the matrix
416*>                     generator for type "j".
417*>     KMAGN(j)        The order of magnitude ( O(1),
418*>                     O(overflow^(1/2) ), O(underflow^(1/2) )
419*> \endverbatim
420*
421*  Authors:
422*  ========
423*
424*> \author Univ. of Tennessee
425*> \author Univ. of California Berkeley
426*> \author Univ. of Colorado Denver
427*> \author NAG Ltd.
428*
429*> \date November 2011
430*
431*> \ingroup single_eig
432*
433*  =====================================================================
434      SUBROUTINE SCHKBD( NSIZES, MVAL, NVAL, NTYPES, DOTYPE, NRHS,
435     $                   ISEED, THRESH, A, LDA, BD, BE, S1, S2, X, LDX,
436     $                   Y, Z, Q, LDQ, PT, LDPT, U, VT, WORK, LWORK,
437     $                   IWORK, NOUT, INFO )
438*
439*  -- LAPACK test routine (version 3.4.0) --
440*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
441*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
442*     November 2011
443*
444*     .. Scalar Arguments ..
445      INTEGER            INFO, LDA, LDPT, LDQ, LDX, LWORK, NOUT, NRHS,
446     $                   NSIZES, NTYPES
447      REAL               THRESH
448*     ..
449*     .. Array Arguments ..
450      LOGICAL            DOTYPE( * )
451      INTEGER            ISEED( 4 ), IWORK( * ), MVAL( * ), NVAL( * )
452      REAL               A( LDA, * ), BD( * ), BE( * ), PT( LDPT, * ),
453     $                   Q( LDQ, * ), S1( * ), S2( * ), U( LDPT, * ),
454     $                   VT( LDPT, * ), WORK( * ), X( LDX, * ),
455     $                   Y( LDX, * ), Z( LDX, * )
456*     ..
457*
458* ======================================================================
459*
460*     .. Parameters ..
461      REAL               ZERO, ONE, TWO, HALF
462      PARAMETER          ( ZERO = 0.0E0, ONE = 1.0E0, TWO = 2.0E0,
463     $                   HALF = 0.5E0 )
464      INTEGER            MAXTYP
465      PARAMETER          ( MAXTYP = 16 )
466*     ..
467*     .. Local Scalars ..
468      LOGICAL            BADMM, BADNN, BIDIAG
469      CHARACTER          UPLO
470      CHARACTER*3        PATH
471      INTEGER            I, IINFO, IMODE, ITYPE, J, JCOL, JSIZE, JTYPE,
472     $                   LOG2UI, M, MINWRK, MMAX, MNMAX, MNMIN, MQ,
473     $                   MTYPES, N, NFAIL, NMAX, NTEST
474      REAL               AMNINV, ANORM, COND, OVFL, RTOVFL, RTUNFL,
475     $                   TEMP1, TEMP2, ULP, ULPINV, UNFL
476*     ..
477*     .. Local Arrays ..
478      INTEGER            IDUM( 1 ), IOLDSD( 4 ), KMAGN( MAXTYP ),
479     $                   KMODE( MAXTYP ), KTYPE( MAXTYP )
480      REAL               DUM( 1 ), DUMMA( 1 ), RESULT( 19 )
481*     ..
482*     .. External Functions ..
483      REAL               SLAMCH, SLARND
484      EXTERNAL           SLAMCH, SLARND
485*     ..
486*     .. External Subroutines ..
487      EXTERNAL           ALASUM, SBDSDC, SBDSQR, SBDT01, SBDT02, SBDT03,
488     $                   SCOPY, SGEBRD, SGEMM, SLABAD, SLACPY, SLAHD2,
489     $                   SLASET, SLATMR, SLATMS, SORGBR, SORT01, XERBLA
490*     ..
491*     .. Intrinsic Functions ..
492      INTRINSIC          ABS, EXP, INT, LOG, MAX, MIN, SQRT
493*     ..
494*     .. Scalars in Common ..
495      LOGICAL            LERR, OK
496      CHARACTER*32       SRNAMT
497      INTEGER            INFOT, NUNIT
498*     ..
499*     .. Common blocks ..
500      COMMON             / INFOC / INFOT, NUNIT, OK, LERR
501      COMMON             / SRNAMC / SRNAMT
502*     ..
503*     .. Data statements ..
504      DATA               KTYPE / 1, 2, 5*4, 5*6, 3*9, 10 /
505      DATA               KMAGN / 2*1, 3*1, 2, 3, 3*1, 2, 3, 1, 2, 3, 0 /
506      DATA               KMODE / 2*0, 4, 3, 1, 4, 4, 4, 3, 1, 4, 4, 0,
507     $                   0, 0, 0 /
508*     ..
509*     .. Executable Statements ..
510*
511*     Check for errors
512*
513      INFO = 0
514*
515      BADMM = .FALSE.
516      BADNN = .FALSE.
517      MMAX = 1
518      NMAX = 1
519      MNMAX = 1
520      MINWRK = 1
521      DO 10 J = 1, NSIZES
522         MMAX = MAX( MMAX, MVAL( J ) )
523         IF( MVAL( J ).LT.0 )
524     $      BADMM = .TRUE.
525         NMAX = MAX( NMAX, NVAL( J ) )
526         IF( NVAL( J ).LT.0 )
527     $      BADNN = .TRUE.
528         MNMAX = MAX( MNMAX, MIN( MVAL( J ), NVAL( J ) ) )
529         MINWRK = MAX( MINWRK, 3*( MVAL( J )+NVAL( J ) ),
530     $            MVAL( J )*( MVAL( J )+MAX( MVAL( J ), NVAL( J ),
531     $            NRHS )+1 )+NVAL( J )*MIN( NVAL( J ), MVAL( J ) ) )
532   10 CONTINUE
533*
534*     Check for errors
535*
536      IF( NSIZES.LT.0 ) THEN
537         INFO = -1
538      ELSE IF( BADMM ) THEN
539         INFO = -2
540      ELSE IF( BADNN ) THEN
541         INFO = -3
542      ELSE IF( NTYPES.LT.0 ) THEN
543         INFO = -4
544      ELSE IF( NRHS.LT.0 ) THEN
545         INFO = -6
546      ELSE IF( LDA.LT.MMAX ) THEN
547         INFO = -11
548      ELSE IF( LDX.LT.MMAX ) THEN
549         INFO = -17
550      ELSE IF( LDQ.LT.MMAX ) THEN
551         INFO = -21
552      ELSE IF( LDPT.LT.MNMAX ) THEN
553         INFO = -23
554      ELSE IF( MINWRK.GT.LWORK ) THEN
555         INFO = -27
556      END IF
557*
558      IF( INFO.NE.0 ) THEN
559         CALL XERBLA( 'SCHKBD', -INFO )
560         RETURN
561      END IF
562*
563*     Initialize constants
564*
565      PATH( 1: 1 ) = 'Single precision'
566      PATH( 2: 3 ) = 'BD'
567      NFAIL = 0
568      NTEST = 0
569      UNFL = SLAMCH( 'Safe minimum' )
570      OVFL = SLAMCH( 'Overflow' )
571      CALL SLABAD( UNFL, OVFL )
572      ULP = SLAMCH( 'Precision' )
573      ULPINV = ONE / ULP
574      LOG2UI = INT( LOG( ULPINV ) / LOG( TWO ) )
575      RTUNFL = SQRT( UNFL )
576      RTOVFL = SQRT( OVFL )
577      INFOT = 0
578*
579*     Loop over sizes, types
580*
581      DO 200 JSIZE = 1, NSIZES
582         M = MVAL( JSIZE )
583         N = NVAL( JSIZE )
584         MNMIN = MIN( M, N )
585         AMNINV = ONE / MAX( M, N, 1 )
586*
587         IF( NSIZES.NE.1 ) THEN
588            MTYPES = MIN( MAXTYP, NTYPES )
589         ELSE
590            MTYPES = MIN( MAXTYP+1, NTYPES )
591         END IF
592*
593         DO 190 JTYPE = 1, MTYPES
594            IF( .NOT.DOTYPE( JTYPE ) )
595     $         GO TO 190
596*
597            DO 20 J = 1, 4
598               IOLDSD( J ) = ISEED( J )
599   20       CONTINUE
600*
601            DO 30 J = 1, 14
602               RESULT( J ) = -ONE
603   30       CONTINUE
604*
605            UPLO = ' '
606*
607*           Compute "A"
608*
609*           Control parameters:
610*
611*           KMAGN  KMODE        KTYPE
612*       =1  O(1)   clustered 1  zero
613*       =2  large  clustered 2  identity
614*       =3  small  exponential  (none)
615*       =4         arithmetic   diagonal, (w/ eigenvalues)
616*       =5         random       symmetric, w/ eigenvalues
617*       =6                      nonsymmetric, w/ singular values
618*       =7                      random diagonal
619*       =8                      random symmetric
620*       =9                      random nonsymmetric
621*       =10                     random bidiagonal (log. distrib.)
622*
623            IF( MTYPES.GT.MAXTYP )
624     $         GO TO 100
625*
626            ITYPE = KTYPE( JTYPE )
627            IMODE = KMODE( JTYPE )
628*
629*           Compute norm
630*
631            GO TO ( 40, 50, 60 )KMAGN( JTYPE )
632*
633   40       CONTINUE
634            ANORM = ONE
635            GO TO 70
636*
637   50       CONTINUE
638            ANORM = ( RTOVFL*ULP )*AMNINV
639            GO TO 70
640*
641   60       CONTINUE
642            ANORM = RTUNFL*MAX( M, N )*ULPINV
643            GO TO 70
644*
645   70       CONTINUE
646*
647            CALL SLASET( 'Full', LDA, N, ZERO, ZERO, A, LDA )
648            IINFO = 0
649            COND = ULPINV
650*
651            BIDIAG = .FALSE.
652            IF( ITYPE.EQ.1 ) THEN
653*
654*              Zero matrix
655*
656               IINFO = 0
657*
658            ELSE IF( ITYPE.EQ.2 ) THEN
659*
660*              Identity
661*
662               DO 80 JCOL = 1, MNMIN
663                  A( JCOL, JCOL ) = ANORM
664   80          CONTINUE
665*
666            ELSE IF( ITYPE.EQ.4 ) THEN
667*
668*              Diagonal Matrix, [Eigen]values Specified
669*
670               CALL SLATMS( MNMIN, MNMIN, 'S', ISEED, 'N', WORK, IMODE,
671     $                      COND, ANORM, 0, 0, 'N', A, LDA,
672     $                      WORK( MNMIN+1 ), IINFO )
673*
674            ELSE IF( ITYPE.EQ.5 ) THEN
675*
676*              Symmetric, eigenvalues specified
677*
678               CALL SLATMS( MNMIN, MNMIN, 'S', ISEED, 'S', WORK, IMODE,
679     $                      COND, ANORM, M, N, 'N', A, LDA,
680     $                      WORK( MNMIN+1 ), IINFO )
681*
682            ELSE IF( ITYPE.EQ.6 ) THEN
683*
684*              Nonsymmetric, singular values specified
685*
686               CALL SLATMS( M, N, 'S', ISEED, 'N', WORK, IMODE, COND,
687     $                      ANORM, M, N, 'N', A, LDA, WORK( MNMIN+1 ),
688     $                      IINFO )
689*
690            ELSE IF( ITYPE.EQ.7 ) THEN
691*
692*              Diagonal, random entries
693*
694               CALL SLATMR( MNMIN, MNMIN, 'S', ISEED, 'N', WORK, 6, ONE,
695     $                      ONE, 'T', 'N', WORK( MNMIN+1 ), 1, ONE,
696     $                      WORK( 2*MNMIN+1 ), 1, ONE, 'N', IWORK, 0, 0,
697     $                      ZERO, ANORM, 'NO', A, LDA, IWORK, IINFO )
698*
699            ELSE IF( ITYPE.EQ.8 ) THEN
700*
701*              Symmetric, random entries
702*
703               CALL SLATMR( MNMIN, MNMIN, 'S', ISEED, 'S', WORK, 6, ONE,
704     $                      ONE, 'T', 'N', WORK( MNMIN+1 ), 1, ONE,
705     $                      WORK( M+MNMIN+1 ), 1, ONE, 'N', IWORK, M, N,
706     $                      ZERO, ANORM, 'NO', A, LDA, IWORK, IINFO )
707*
708            ELSE IF( ITYPE.EQ.9 ) THEN
709*
710*              Nonsymmetric, random entries
711*
712               CALL SLATMR( M, N, 'S', ISEED, 'N', WORK, 6, ONE, ONE,
713     $                      'T', 'N', WORK( MNMIN+1 ), 1, ONE,
714     $                      WORK( M+MNMIN+1 ), 1, ONE, 'N', IWORK, M, N,
715     $                      ZERO, ANORM, 'NO', A, LDA, IWORK, IINFO )
716*
717            ELSE IF( ITYPE.EQ.10 ) THEN
718*
719*              Bidiagonal, random entries
720*
721               TEMP1 = -TWO*LOG( ULP )
722               DO 90 J = 1, MNMIN
723                  BD( J ) = EXP( TEMP1*SLARND( 2, ISEED ) )
724                  IF( J.LT.MNMIN )
725     $               BE( J ) = EXP( TEMP1*SLARND( 2, ISEED ) )
726   90          CONTINUE
727*
728               IINFO = 0
729               BIDIAG = .TRUE.
730               IF( M.GE.N ) THEN
731                  UPLO = 'U'
732               ELSE
733                  UPLO = 'L'
734               END IF
735            ELSE
736               IINFO = 1
737            END IF
738*
739            IF( IINFO.EQ.0 ) THEN
740*
741*              Generate Right-Hand Side
742*
743               IF( BIDIAG ) THEN
744                  CALL SLATMR( MNMIN, NRHS, 'S', ISEED, 'N', WORK, 6,
745     $                         ONE, ONE, 'T', 'N', WORK( MNMIN+1 ), 1,
746     $                         ONE, WORK( 2*MNMIN+1 ), 1, ONE, 'N',
747     $                         IWORK, MNMIN, NRHS, ZERO, ONE, 'NO', Y,
748     $                         LDX, IWORK, IINFO )
749               ELSE
750                  CALL SLATMR( M, NRHS, 'S', ISEED, 'N', WORK, 6, ONE,
751     $                         ONE, 'T', 'N', WORK( M+1 ), 1, ONE,
752     $                         WORK( 2*M+1 ), 1, ONE, 'N', IWORK, M,
753     $                         NRHS, ZERO, ONE, 'NO', X, LDX, IWORK,
754     $                         IINFO )
755               END IF
756            END IF
757*
758*           Error Exit
759*
760            IF( IINFO.NE.0 ) THEN
761               WRITE( NOUT, FMT = 9998 )'Generator', IINFO, M, N,
762     $            JTYPE, IOLDSD
763               INFO = ABS( IINFO )
764               RETURN
765            END IF
766*
767  100       CONTINUE
768*
769*           Call SGEBRD and SORGBR to compute B, Q, and P, do tests.
770*
771            IF( .NOT.BIDIAG ) THEN
772*
773*              Compute transformations to reduce A to bidiagonal form:
774*              B := Q' * A * P.
775*
776               CALL SLACPY( ' ', M, N, A, LDA, Q, LDQ )
777               CALL SGEBRD( M, N, Q, LDQ, BD, BE, WORK, WORK( MNMIN+1 ),
778     $                      WORK( 2*MNMIN+1 ), LWORK-2*MNMIN, IINFO )
779*
780*              Check error code from SGEBRD.
781*
782               IF( IINFO.NE.0 ) THEN
783                  WRITE( NOUT, FMT = 9998 )'SGEBRD', IINFO, M, N,
784     $               JTYPE, IOLDSD
785                  INFO = ABS( IINFO )
786                  RETURN
787               END IF
788*
789               CALL SLACPY( ' ', M, N, Q, LDQ, PT, LDPT )
790               IF( M.GE.N ) THEN
791                  UPLO = 'U'
792               ELSE
793                  UPLO = 'L'
794               END IF
795*
796*              Generate Q
797*
798               MQ = M
799               IF( NRHS.LE.0 )
800     $            MQ = MNMIN
801               CALL SORGBR( 'Q', M, MQ, N, Q, LDQ, WORK,
802     $                      WORK( 2*MNMIN+1 ), LWORK-2*MNMIN, IINFO )
803*
804*              Check error code from SORGBR.
805*
806               IF( IINFO.NE.0 ) THEN
807                  WRITE( NOUT, FMT = 9998 )'SORGBR(Q)', IINFO, M, N,
808     $               JTYPE, IOLDSD
809                  INFO = ABS( IINFO )
810                  RETURN
811               END IF
812*
813*              Generate P'
814*
815               CALL SORGBR( 'P', MNMIN, N, M, PT, LDPT, WORK( MNMIN+1 ),
816     $                      WORK( 2*MNMIN+1 ), LWORK-2*MNMIN, IINFO )
817*
818*              Check error code from SORGBR.
819*
820               IF( IINFO.NE.0 ) THEN
821                  WRITE( NOUT, FMT = 9998 )'SORGBR(P)', IINFO, M, N,
822     $               JTYPE, IOLDSD
823                  INFO = ABS( IINFO )
824                  RETURN
825               END IF
826*
827*              Apply Q' to an M by NRHS matrix X:  Y := Q' * X.
828*
829               CALL SGEMM( 'Transpose', 'No transpose', M, NRHS, M, ONE,
830     $                     Q, LDQ, X, LDX, ZERO, Y, LDX )
831*
832*              Test 1:  Check the decomposition A := Q * B * PT
833*                   2:  Check the orthogonality of Q
834*                   3:  Check the orthogonality of PT
835*
836               CALL SBDT01( M, N, 1, A, LDA, Q, LDQ, BD, BE, PT, LDPT,
837     $                      WORK, RESULT( 1 ) )
838               CALL SORT01( 'Columns', M, MQ, Q, LDQ, WORK, LWORK,
839     $                      RESULT( 2 ) )
840               CALL SORT01( 'Rows', MNMIN, N, PT, LDPT, WORK, LWORK,
841     $                      RESULT( 3 ) )
842            END IF
843*
844*           Use SBDSQR to form the SVD of the bidiagonal matrix B:
845*           B := U * S1 * VT, and compute Z = U' * Y.
846*
847            CALL SCOPY( MNMIN, BD, 1, S1, 1 )
848            IF( MNMIN.GT.0 )
849     $         CALL SCOPY( MNMIN-1, BE, 1, WORK, 1 )
850            CALL SLACPY( ' ', M, NRHS, Y, LDX, Z, LDX )
851            CALL SLASET( 'Full', MNMIN, MNMIN, ZERO, ONE, U, LDPT )
852            CALL SLASET( 'Full', MNMIN, MNMIN, ZERO, ONE, VT, LDPT )
853*
854            CALL SBDSQR( UPLO, MNMIN, MNMIN, MNMIN, NRHS, S1, WORK, VT,
855     $                   LDPT, U, LDPT, Z, LDX, WORK( MNMIN+1 ), IINFO )
856*
857*           Check error code from SBDSQR.
858*
859            IF( IINFO.NE.0 ) THEN
860               WRITE( NOUT, FMT = 9998 )'SBDSQR(vects)', IINFO, M, N,
861     $            JTYPE, IOLDSD
862               INFO = ABS( IINFO )
863               IF( IINFO.LT.0 ) THEN
864                  RETURN
865               ELSE
866                  RESULT( 4 ) = ULPINV
867                  GO TO 170
868               END IF
869            END IF
870*
871*           Use SBDSQR to compute only the singular values of the
872*           bidiagonal matrix B;  U, VT, and Z should not be modified.
873*
874            CALL SCOPY( MNMIN, BD, 1, S2, 1 )
875            IF( MNMIN.GT.0 )
876     $         CALL SCOPY( MNMIN-1, BE, 1, WORK, 1 )
877*
878            CALL SBDSQR( UPLO, MNMIN, 0, 0, 0, S2, WORK, VT, LDPT, U,
879     $                   LDPT, Z, LDX, WORK( MNMIN+1 ), IINFO )
880*
881*           Check error code from SBDSQR.
882*
883            IF( IINFO.NE.0 ) THEN
884               WRITE( NOUT, FMT = 9998 )'SBDSQR(values)', IINFO, M, N,
885     $            JTYPE, IOLDSD
886               INFO = ABS( IINFO )
887               IF( IINFO.LT.0 ) THEN
888                  RETURN
889               ELSE
890                  RESULT( 9 ) = ULPINV
891                  GO TO 170
892               END IF
893            END IF
894*
895*           Test 4:  Check the decomposition B := U * S1 * VT
896*                5:  Check the computation Z := U' * Y
897*                6:  Check the orthogonality of U
898*                7:  Check the orthogonality of VT
899*
900            CALL SBDT03( UPLO, MNMIN, 1, BD, BE, U, LDPT, S1, VT, LDPT,
901     $                   WORK, RESULT( 4 ) )
902            CALL SBDT02( MNMIN, NRHS, Y, LDX, Z, LDX, U, LDPT, WORK,
903     $                   RESULT( 5 ) )
904            CALL SORT01( 'Columns', MNMIN, MNMIN, U, LDPT, WORK, LWORK,
905     $                   RESULT( 6 ) )
906            CALL SORT01( 'Rows', MNMIN, MNMIN, VT, LDPT, WORK, LWORK,
907     $                   RESULT( 7 ) )
908*
909*           Test 8:  Check that the singular values are sorted in
910*                    non-increasing order and are non-negative
911*
912            RESULT( 8 ) = ZERO
913            DO 110 I = 1, MNMIN - 1
914               IF( S1( I ).LT.S1( I+1 ) )
915     $            RESULT( 8 ) = ULPINV
916               IF( S1( I ).LT.ZERO )
917     $            RESULT( 8 ) = ULPINV
918  110       CONTINUE
919            IF( MNMIN.GE.1 ) THEN
920               IF( S1( MNMIN ).LT.ZERO )
921     $            RESULT( 8 ) = ULPINV
922            END IF
923*
924*           Test 9:  Compare SBDSQR with and without singular vectors
925*
926            TEMP2 = ZERO
927*
928            DO 120 J = 1, MNMIN
929               TEMP1 = ABS( S1( J )-S2( J ) ) /
930     $                 MAX( SQRT( UNFL )*MAX( S1( 1 ), ONE ),
931     $                 ULP*MAX( ABS( S1( J ) ), ABS( S2( J ) ) ) )
932               TEMP2 = MAX( TEMP1, TEMP2 )
933  120       CONTINUE
934*
935            RESULT( 9 ) = TEMP2
936*
937*           Test 10:  Sturm sequence test of singular values
938*                     Go up by factors of two until it succeeds
939*
940            TEMP1 = THRESH*( HALF-ULP )
941*
942            DO 130 J = 0, LOG2UI
943*               CALL SSVDCH( MNMIN, BD, BE, S1, TEMP1, IINFO )
944               IF( IINFO.EQ.0 )
945     $            GO TO 140
946               TEMP1 = TEMP1*TWO
947  130       CONTINUE
948*
949  140       CONTINUE
950            RESULT( 10 ) = TEMP1
951*
952*           Use SBDSQR to form the decomposition A := (QU) S (VT PT)
953*           from the bidiagonal form A := Q B PT.
954*
955            IF( .NOT.BIDIAG ) THEN
956               CALL SCOPY( MNMIN, BD, 1, S2, 1 )
957               IF( MNMIN.GT.0 )
958     $            CALL SCOPY( MNMIN-1, BE, 1, WORK, 1 )
959*
960               CALL SBDSQR( UPLO, MNMIN, N, M, NRHS, S2, WORK, PT, LDPT,
961     $                      Q, LDQ, Y, LDX, WORK( MNMIN+1 ), IINFO )
962*
963*              Test 11:  Check the decomposition A := Q*U * S2 * VT*PT
964*                   12:  Check the computation Z := U' * Q' * X
965*                   13:  Check the orthogonality of Q*U
966*                   14:  Check the orthogonality of VT*PT
967*
968               CALL SBDT01( M, N, 0, A, LDA, Q, LDQ, S2, DUMMA, PT,
969     $                      LDPT, WORK, RESULT( 11 ) )
970               CALL SBDT02( M, NRHS, X, LDX, Y, LDX, Q, LDQ, WORK,
971     $                      RESULT( 12 ) )
972               CALL SORT01( 'Columns', M, MQ, Q, LDQ, WORK, LWORK,
973     $                      RESULT( 13 ) )
974               CALL SORT01( 'Rows', MNMIN, N, PT, LDPT, WORK, LWORK,
975     $                      RESULT( 14 ) )
976            END IF
977*
978*           Use SBDSDC to form the SVD of the bidiagonal matrix B:
979*           B := U * S1 * VT
980*
981            CALL SCOPY( MNMIN, BD, 1, S1, 1 )
982            IF( MNMIN.GT.0 )
983     $         CALL SCOPY( MNMIN-1, BE, 1, WORK, 1 )
984            CALL SLASET( 'Full', MNMIN, MNMIN, ZERO, ONE, U, LDPT )
985            CALL SLASET( 'Full', MNMIN, MNMIN, ZERO, ONE, VT, LDPT )
986*
987            CALL SBDSDC( UPLO, 'I', MNMIN, S1, WORK, U, LDPT, VT, LDPT,
988     $                   DUM, IDUM, WORK( MNMIN+1 ), IWORK, IINFO )
989*
990*           Check error code from SBDSDC.
991*
992            IF( IINFO.NE.0 ) THEN
993               WRITE( NOUT, FMT = 9998 )'SBDSDC(vects)', IINFO, M, N,
994     $            JTYPE, IOLDSD
995               INFO = ABS( IINFO )
996               IF( IINFO.LT.0 ) THEN
997                  RETURN
998               ELSE
999                  RESULT( 15 ) = ULPINV
1000                  GO TO 170
1001               END IF
1002            END IF
1003*
1004*           Use SBDSDC to compute only the singular values of the
1005*           bidiagonal matrix B;  U and VT should not be modified.
1006*
1007            CALL SCOPY( MNMIN, BD, 1, S2, 1 )
1008            IF( MNMIN.GT.0 )
1009     $         CALL SCOPY( MNMIN-1, BE, 1, WORK, 1 )
1010*
1011            CALL SBDSDC( UPLO, 'N', MNMIN, S2, WORK, DUM, 1, DUM, 1,
1012     $                   DUM, IDUM, WORK( MNMIN+1 ), IWORK, IINFO )
1013*
1014*           Check error code from SBDSDC.
1015*
1016            IF( IINFO.NE.0 ) THEN
1017               WRITE( NOUT, FMT = 9998 )'SBDSDC(values)', IINFO, M, N,
1018     $            JTYPE, IOLDSD
1019               INFO = ABS( IINFO )
1020               IF( IINFO.LT.0 ) THEN
1021                  RETURN
1022               ELSE
1023                  RESULT( 18 ) = ULPINV
1024                  GO TO 170
1025               END IF
1026            END IF
1027*
1028*           Test 15:  Check the decomposition B := U * S1 * VT
1029*                16:  Check the orthogonality of U
1030*                17:  Check the orthogonality of VT
1031*
1032            CALL SBDT03( UPLO, MNMIN, 1, BD, BE, U, LDPT, S1, VT, LDPT,
1033     $                   WORK, RESULT( 15 ) )
1034            CALL SORT01( 'Columns', MNMIN, MNMIN, U, LDPT, WORK, LWORK,
1035     $                   RESULT( 16 ) )
1036            CALL SORT01( 'Rows', MNMIN, MNMIN, VT, LDPT, WORK, LWORK,
1037     $                   RESULT( 17 ) )
1038*
1039*           Test 18:  Check that the singular values are sorted in
1040*                     non-increasing order and are non-negative
1041*
1042            RESULT( 18 ) = ZERO
1043            DO 150 I = 1, MNMIN - 1
1044               IF( S1( I ).LT.S1( I+1 ) )
1045     $            RESULT( 18 ) = ULPINV
1046               IF( S1( I ).LT.ZERO )
1047     $            RESULT( 18 ) = ULPINV
1048  150       CONTINUE
1049            IF( MNMIN.GE.1 ) THEN
1050               IF( S1( MNMIN ).LT.ZERO )
1051     $            RESULT( 18 ) = ULPINV
1052            END IF
1053*
1054*           Test 19:  Compare SBDSQR with and without singular vectors
1055*
1056            TEMP2 = ZERO
1057*
1058            DO 160 J = 1, MNMIN
1059               TEMP1 = ABS( S1( J )-S2( J ) ) /
1060     $                 MAX( SQRT( UNFL )*MAX( S1( 1 ), ONE ),
1061     $                 ULP*MAX( ABS( S1( 1 ) ), ABS( S2( 1 ) ) ) )
1062               TEMP2 = MAX( TEMP1, TEMP2 )
1063  160       CONTINUE
1064*
1065            RESULT( 19 ) = TEMP2
1066*
1067*           End of Loop -- Check for RESULT(j) > THRESH
1068*
1069  170       CONTINUE
1070            DO 180 J = 1, 19
1071               IF( RESULT( J ).GE.THRESH ) THEN
1072                  IF( NFAIL.EQ.0 )
1073     $               CALL SLAHD2( NOUT, PATH )
1074                  WRITE( NOUT, FMT = 9999 )M, N, JTYPE, IOLDSD, J,
1075     $               RESULT( J )
1076                  NFAIL = NFAIL + 1
1077               END IF
1078  180       CONTINUE
1079            IF( .NOT.BIDIAG ) THEN
1080               NTEST = NTEST + 19
1081            ELSE
1082               NTEST = NTEST + 5
1083            END IF
1084*
1085  190    CONTINUE
1086  200 CONTINUE
1087*
1088*     Summary
1089*
1090      CALL ALASUM( PATH, NOUT, NFAIL, NTEST, 0 )
1091*
1092      RETURN
1093*
1094*     End of SCHKBD
1095*
1096 9999 FORMAT( ' M=', I5, ', N=', I5, ', type ', I2, ', seed=',
1097     $      4( I4, ',' ), ' test(', I2, ')=', G11.4 )
1098 9998 FORMAT( ' SCHKBD: ', A, ' returned INFO=', I6, '.', / 9X, 'M=',
1099     $      I6, ', N=', I6, ', JTYPE=', I6, ', ISEED=(', 3( I5, ',' ),
1100     $      I5, ')' )
1101*
1102      END
1103