1*> \brief \b SCHKPT
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 SCHKPT( DOTYPE, NN, NVAL, NNS, NSVAL, THRESH, TSTERR,
12*                          A, D, E, B, X, XACT, WORK, RWORK, NOUT )
13*
14*       .. Scalar Arguments ..
15*       LOGICAL            TSTERR
16*       INTEGER            NN, NNS, NOUT
17*       REAL               THRESH
18*       ..
19*       .. Array Arguments ..
20*       LOGICAL            DOTYPE( * )
21*       INTEGER            NSVAL( * ), NVAL( * )
22*       REAL               A( * ), B( * ), D( * ), E( * ), RWORK( * ),
23*      $                   WORK( * ), X( * ), XACT( * )
24*       ..
25*
26*
27*> \par Purpose:
28*  =============
29*>
30*> \verbatim
31*>
32*> SCHKPT tests SPTTRF, -TRS, -RFS, and -CON
33*> \endverbatim
34*
35*  Arguments:
36*  ==========
37*
38*> \param[in] DOTYPE
39*> \verbatim
40*>          DOTYPE is LOGICAL array, dimension (NTYPES)
41*>          The matrix types to be used for testing.  Matrices of type j
42*>          (for 1 <= j <= NTYPES) are used for testing if DOTYPE(j) =
43*>          .TRUE.; if DOTYPE(j) = .FALSE., then type j is not used.
44*> \endverbatim
45*>
46*> \param[in] NN
47*> \verbatim
48*>          NN is INTEGER
49*>          The number of values of N contained in the vector NVAL.
50*> \endverbatim
51*>
52*> \param[in] NVAL
53*> \verbatim
54*>          NVAL is INTEGER array, dimension (NN)
55*>          The values of the matrix dimension N.
56*> \endverbatim
57*>
58*> \param[in] NNS
59*> \verbatim
60*>          NNS is INTEGER
61*>          The number of values of NRHS contained in the vector NSVAL.
62*> \endverbatim
63*>
64*> \param[in] NSVAL
65*> \verbatim
66*>          NSVAL is INTEGER array, dimension (NNS)
67*>          The values of the number of right hand sides NRHS.
68*> \endverbatim
69*>
70*> \param[in] THRESH
71*> \verbatim
72*>          THRESH is REAL
73*>          The threshold value for the test ratios.  A result is
74*>          included in the output file if RESULT >= THRESH.  To have
75*>          every test ratio printed, use THRESH = 0.
76*> \endverbatim
77*>
78*> \param[in] TSTERR
79*> \verbatim
80*>          TSTERR is LOGICAL
81*>          Flag that indicates whether error exits are to be tested.
82*> \endverbatim
83*>
84*> \param[out] A
85*> \verbatim
86*>          A is REAL array, dimension (NMAX*2)
87*> \endverbatim
88*>
89*> \param[out] D
90*> \verbatim
91*>          D is REAL array, dimension (NMAX*2)
92*> \endverbatim
93*>
94*> \param[out] E
95*> \verbatim
96*>          E is REAL array, dimension (NMAX*2)
97*> \endverbatim
98*>
99*> \param[out] B
100*> \verbatim
101*>          B is REAL array, dimension (NMAX*NSMAX)
102*>          where NSMAX is the largest entry in NSVAL.
103*> \endverbatim
104*>
105*> \param[out] X
106*> \verbatim
107*>          X is REAL array, dimension (NMAX*NSMAX)
108*> \endverbatim
109*>
110*> \param[out] XACT
111*> \verbatim
112*>          XACT is REAL array, dimension (NMAX*NSMAX)
113*> \endverbatim
114*>
115*> \param[out] WORK
116*> \verbatim
117*>          WORK is REAL array, dimension
118*>                      (NMAX*max(3,NSMAX))
119*> \endverbatim
120*>
121*> \param[out] RWORK
122*> \verbatim
123*>          RWORK is REAL array, dimension
124*>                      (max(NMAX,2*NSMAX))
125*> \endverbatim
126*>
127*> \param[in] NOUT
128*> \verbatim
129*>          NOUT is INTEGER
130*>          The unit number for output.
131*> \endverbatim
132*
133*  Authors:
134*  ========
135*
136*> \author Univ. of Tennessee
137*> \author Univ. of California Berkeley
138*> \author Univ. of Colorado Denver
139*> \author NAG Ltd.
140*
141*> \date November 2011
142*
143*> \ingroup single_lin
144*
145*  =====================================================================
146      SUBROUTINE SCHKPT( DOTYPE, NN, NVAL, NNS, NSVAL, THRESH, TSTERR,
147     $                   A, D, E, B, X, XACT, WORK, RWORK, NOUT )
148*
149*  -- LAPACK test routine (version 3.4.0) --
150*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
151*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
152*     November 2011
153*
154*     .. Scalar Arguments ..
155      LOGICAL            TSTERR
156      INTEGER            NN, NNS, NOUT
157      REAL               THRESH
158*     ..
159*     .. Array Arguments ..
160      LOGICAL            DOTYPE( * )
161      INTEGER            NSVAL( * ), NVAL( * )
162      REAL               A( * ), B( * ), D( * ), E( * ), RWORK( * ),
163     $                   WORK( * ), X( * ), XACT( * )
164*     ..
165*
166*  =====================================================================
167*
168*     .. Parameters ..
169      REAL               ONE, ZERO
170      PARAMETER          ( ONE = 1.0E+0, ZERO = 0.0E+0 )
171      INTEGER            NTYPES
172      PARAMETER          ( NTYPES = 12 )
173      INTEGER            NTESTS
174      PARAMETER          ( NTESTS = 7 )
175*     ..
176*     .. Local Scalars ..
177      LOGICAL            ZEROT
178      CHARACTER          DIST, TYPE
179      CHARACTER*3        PATH
180      INTEGER            I, IA, IMAT, IN, INFO, IRHS, IX, IZERO, J, K,
181     $                   KL, KU, LDA, MODE, N, NERRS, NFAIL, NIMAT,
182     $                   NRHS, NRUN
183      REAL               AINVNM, ANORM, COND, DMAX, RCOND, RCONDC
184*     ..
185*     .. Local Arrays ..
186      INTEGER            ISEED( 4 ), ISEEDY( 4 )
187      REAL               RESULT( NTESTS ), Z( 3 )
188*     ..
189*     .. External Functions ..
190      INTEGER            ISAMAX
191      REAL               SASUM, SGET06, SLANST
192      EXTERNAL           ISAMAX, SASUM, SGET06, SLANST
193*     ..
194*     .. External Subroutines ..
195      EXTERNAL           ALAERH, ALAHD, ALASUM, SCOPY, SERRGT, SGET04,
196     $                   SLACPY, SLAPTM, SLARNV, SLATB4, SLATMS, SPTCON,
197     $                   SPTRFS, SPTT01, SPTT02, SPTT05, SPTTRF, SPTTRS,
198     $                   SSCAL
199*     ..
200*     .. Intrinsic Functions ..
201      INTRINSIC          ABS, MAX
202*     ..
203*     .. Scalars in Common ..
204      LOGICAL            LERR, OK
205      CHARACTER*32       SRNAMT
206      INTEGER            INFOT, NUNIT
207*     ..
208*     .. Common blocks ..
209      COMMON             / INFOC / INFOT, NUNIT, OK, LERR
210      COMMON             / SRNAMC / SRNAMT
211*     ..
212*     .. Data statements ..
213      DATA               ISEEDY / 0, 0, 0, 1 /
214*     ..
215*     .. Executable Statements ..
216*
217      PATH( 1: 1 ) = 'Single precision'
218      PATH( 2: 3 ) = 'PT'
219      NRUN = 0
220      NFAIL = 0
221      NERRS = 0
222      DO 10 I = 1, 4
223         ISEED( I ) = ISEEDY( I )
224   10 CONTINUE
225*
226*     Test the error exits
227*
228      IF( TSTERR )
229     $   CALL SERRGT( PATH, NOUT )
230      INFOT = 0
231*
232      DO 110 IN = 1, NN
233*
234*        Do for each value of N in NVAL.
235*
236         N = NVAL( IN )
237         LDA = MAX( 1, N )
238         NIMAT = NTYPES
239         IF( N.LE.0 )
240     $      NIMAT = 1
241*
242         DO 100 IMAT = 1, NIMAT
243*
244*           Do the tests only if DOTYPE( IMAT ) is true.
245*
246            IF( N.GT.0 .AND. .NOT.DOTYPE( IMAT ) )
247     $         GO TO 100
248*
249*           Set up parameters with SLATB4.
250*
251            CALL SLATB4( PATH, IMAT, N, N, TYPE, KL, KU, ANORM, MODE,
252     $                   COND, DIST )
253*
254            ZEROT = IMAT.GE.8 .AND. IMAT.LE.10
255            IF( IMAT.LE.6 ) THEN
256*
257*              Type 1-6:  generate a symmetric tridiagonal matrix of
258*              known condition number in lower triangular band storage.
259*
260               SRNAMT = 'SLATMS'
261               CALL SLATMS( N, N, DIST, ISEED, TYPE, RWORK, MODE, COND,
262     $                      ANORM, KL, KU, 'B', A, 2, WORK, INFO )
263*
264*              Check the error code from SLATMS.
265*
266               IF( INFO.NE.0 ) THEN
267                  CALL ALAERH( PATH, 'SLATMS', INFO, 0, ' ', N, N, KL,
268     $                         KU, -1, IMAT, NFAIL, NERRS, NOUT )
269                  GO TO 100
270               END IF
271               IZERO = 0
272*
273*              Copy the matrix to D and E.
274*
275               IA = 1
276               DO 20 I = 1, N - 1
277                  D( I ) = A( IA )
278                  E( I ) = A( IA+1 )
279                  IA = IA + 2
280   20          CONTINUE
281               IF( N.GT.0 )
282     $            D( N ) = A( IA )
283            ELSE
284*
285*              Type 7-12:  generate a diagonally dominant matrix with
286*              unknown condition number in the vectors D and E.
287*
288               IF( .NOT.ZEROT .OR. .NOT.DOTYPE( 7 ) ) THEN
289*
290*                 Let D and E have values from [-1,1].
291*
292                  CALL SLARNV( 2, ISEED, N, D )
293                  CALL SLARNV( 2, ISEED, N-1, E )
294*
295*                 Make the tridiagonal matrix diagonally dominant.
296*
297                  IF( N.EQ.1 ) THEN
298                     D( 1 ) = ABS( D( 1 ) )
299                  ELSE
300                     D( 1 ) = ABS( D( 1 ) ) + ABS( E( 1 ) )
301                     D( N ) = ABS( D( N ) ) + ABS( E( N-1 ) )
302                     DO 30 I = 2, N - 1
303                        D( I ) = ABS( D( I ) ) + ABS( E( I ) ) +
304     $                           ABS( E( I-1 ) )
305   30                CONTINUE
306                  END IF
307*
308*                 Scale D and E so the maximum element is ANORM.
309*
310                  IX = ISAMAX( N, D, 1 )
311                  DMAX = D( IX )
312                  CALL SSCAL( N, ANORM / DMAX, D, 1 )
313                  CALL SSCAL( N-1, ANORM / DMAX, E, 1 )
314*
315               ELSE IF( IZERO.GT.0 ) THEN
316*
317*                 Reuse the last matrix by copying back the zeroed out
318*                 elements.
319*
320                  IF( IZERO.EQ.1 ) THEN
321                     D( 1 ) = Z( 2 )
322                     IF( N.GT.1 )
323     $                  E( 1 ) = Z( 3 )
324                  ELSE IF( IZERO.EQ.N ) THEN
325                     E( N-1 ) = Z( 1 )
326                     D( N ) = Z( 2 )
327                  ELSE
328                     E( IZERO-1 ) = Z( 1 )
329                     D( IZERO ) = Z( 2 )
330                     E( IZERO ) = Z( 3 )
331                  END IF
332               END IF
333*
334*              For types 8-10, set one row and column of the matrix to
335*              zero.
336*
337               IZERO = 0
338               IF( IMAT.EQ.8 ) THEN
339                  IZERO = 1
340                  Z( 2 ) = D( 1 )
341                  D( 1 ) = ZERO
342                  IF( N.GT.1 ) THEN
343                     Z( 3 ) = E( 1 )
344                     E( 1 ) = ZERO
345                  END IF
346               ELSE IF( IMAT.EQ.9 ) THEN
347                  IZERO = N
348                  IF( N.GT.1 ) THEN
349                     Z( 1 ) = E( N-1 )
350                     E( N-1 ) = ZERO
351                  END IF
352                  Z( 2 ) = D( N )
353                  D( N ) = ZERO
354               ELSE IF( IMAT.EQ.10 ) THEN
355                  IZERO = ( N+1 ) / 2
356                  IF( IZERO.GT.1 ) THEN
357                     Z( 1 ) = E( IZERO-1 )
358                     E( IZERO-1 ) = ZERO
359                     Z( 3 ) = E( IZERO )
360                     E( IZERO ) = ZERO
361                  END IF
362                  Z( 2 ) = D( IZERO )
363                  D( IZERO ) = ZERO
364               END IF
365            END IF
366*
367            CALL SCOPY( N, D, 1, D( N+1 ), 1 )
368            IF( N.GT.1 )
369     $         CALL SCOPY( N-1, E, 1, E( N+1 ), 1 )
370*
371*+    TEST 1
372*           Factor A as L*D*L' and compute the ratio
373*              norm(L*D*L' - A) / (n * norm(A) * EPS )
374*
375            CALL SPTTRF( N, D( N+1 ), E( N+1 ), INFO )
376*
377*           Check error code from SPTTRF.
378*
379            IF( INFO.NE.IZERO ) THEN
380               CALL ALAERH( PATH, 'SPTTRF', INFO, IZERO, ' ', N, N, -1,
381     $                      -1, -1, IMAT, NFAIL, NERRS, NOUT )
382               GO TO 100
383            END IF
384*
385            IF( INFO.GT.0 ) THEN
386               RCONDC = ZERO
387               GO TO 90
388            END IF
389*
390            CALL SPTT01( N, D, E, D( N+1 ), E( N+1 ), WORK,
391     $                   RESULT( 1 ) )
392*
393*           Print the test ratio if greater than or equal to THRESH.
394*
395            IF( RESULT( 1 ).GE.THRESH ) THEN
396               IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
397     $            CALL ALAHD( NOUT, PATH )
398               WRITE( NOUT, FMT = 9999 )N, IMAT, 1, RESULT( 1 )
399               NFAIL = NFAIL + 1
400            END IF
401            NRUN = NRUN + 1
402*
403*           Compute RCONDC = 1 / (norm(A) * norm(inv(A))
404*
405*           Compute norm(A).
406*
407            ANORM = SLANST( '1', N, D, E )
408*
409*           Use SPTTRS to solve for one column at a time of inv(A),
410*           computing the maximum column sum as we go.
411*
412            AINVNM = ZERO
413            DO 50 I = 1, N
414               DO 40 J = 1, N
415                  X( J ) = ZERO
416   40          CONTINUE
417               X( I ) = ONE
418               CALL SPTTRS( N, 1, D( N+1 ), E( N+1 ), X, LDA, INFO )
419               AINVNM = MAX( AINVNM, SASUM( N, X, 1 ) )
420   50       CONTINUE
421            RCONDC = ONE / MAX( ONE, ANORM*AINVNM )
422*
423            DO 80 IRHS = 1, NNS
424               NRHS = NSVAL( IRHS )
425*
426*           Generate NRHS random solution vectors.
427*
428               IX = 1
429               DO 60 J = 1, NRHS
430                  CALL SLARNV( 2, ISEED, N, XACT( IX ) )
431                  IX = IX + LDA
432   60          CONTINUE
433*
434*           Set the right hand side.
435*
436               CALL SLAPTM( N, NRHS, ONE, D, E, XACT, LDA, ZERO, B,
437     $                      LDA )
438*
439*+    TEST 2
440*           Solve A*x = b and compute the residual.
441*
442               CALL SLACPY( 'Full', N, NRHS, B, LDA, X, LDA )
443               CALL SPTTRS( N, NRHS, D( N+1 ), E( N+1 ), X, LDA, INFO )
444*
445*           Check error code from SPTTRS.
446*
447               IF( INFO.NE.0 )
448     $            CALL ALAERH( PATH, 'SPTTRS', INFO, 0, ' ', N, N, -1,
449     $                         -1, NRHS, IMAT, NFAIL, NERRS, NOUT )
450*
451               CALL SLACPY( 'Full', N, NRHS, B, LDA, WORK, LDA )
452               CALL SPTT02( N, NRHS, D, E, X, LDA, WORK, LDA,
453     $                      RESULT( 2 ) )
454*
455*+    TEST 3
456*           Check solution from generated exact solution.
457*
458               CALL SGET04( N, NRHS, X, LDA, XACT, LDA, RCONDC,
459     $                      RESULT( 3 ) )
460*
461*+    TESTS 4, 5, and 6
462*           Use iterative refinement to improve the solution.
463*
464               SRNAMT = 'SPTRFS'
465               CALL SPTRFS( N, NRHS, D, E, D( N+1 ), E( N+1 ), B, LDA,
466     $                      X, LDA, RWORK, RWORK( NRHS+1 ), WORK, INFO )
467*
468*           Check error code from SPTRFS.
469*
470               IF( INFO.NE.0 )
471     $            CALL ALAERH( PATH, 'SPTRFS', INFO, 0, ' ', N, N, -1,
472     $                         -1, NRHS, IMAT, NFAIL, NERRS, NOUT )
473*
474               CALL SGET04( N, NRHS, X, LDA, XACT, LDA, RCONDC,
475     $                      RESULT( 4 ) )
476               CALL SPTT05( N, NRHS, D, E, B, LDA, X, LDA, XACT, LDA,
477     $                      RWORK, RWORK( NRHS+1 ), RESULT( 5 ) )
478*
479*           Print information about the tests that did not pass the
480*           threshold.
481*
482               DO 70 K = 2, 6
483                  IF( RESULT( K ).GE.THRESH ) THEN
484                     IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
485     $                  CALL ALAHD( NOUT, PATH )
486                     WRITE( NOUT, FMT = 9998 )N, NRHS, IMAT, K,
487     $                  RESULT( K )
488                     NFAIL = NFAIL + 1
489                  END IF
490   70          CONTINUE
491               NRUN = NRUN + 5
492   80       CONTINUE
493*
494*+    TEST 7
495*           Estimate the reciprocal of the condition number of the
496*           matrix.
497*
498   90       CONTINUE
499            SRNAMT = 'SPTCON'
500            CALL SPTCON( N, D( N+1 ), E( N+1 ), ANORM, RCOND, RWORK,
501     $                   INFO )
502*
503*           Check error code from SPTCON.
504*
505            IF( INFO.NE.0 )
506     $         CALL ALAERH( PATH, 'SPTCON', INFO, 0, ' ', N, N, -1, -1,
507     $                      -1, IMAT, NFAIL, NERRS, NOUT )
508*
509            RESULT( 7 ) = SGET06( RCOND, RCONDC )
510*
511*           Print the test ratio if greater than or equal to THRESH.
512*
513            IF( RESULT( 7 ).GE.THRESH ) THEN
514               IF( NFAIL.EQ.0 .AND. NERRS.EQ.0 )
515     $            CALL ALAHD( NOUT, PATH )
516               WRITE( NOUT, FMT = 9999 )N, IMAT, 7, RESULT( 7 )
517               NFAIL = NFAIL + 1
518            END IF
519            NRUN = NRUN + 1
520  100    CONTINUE
521  110 CONTINUE
522*
523*     Print a summary of the results.
524*
525      CALL ALASUM( PATH, NOUT, NFAIL, NRUN, NERRS )
526*
527 9999 FORMAT( ' N =', I5, ', type ', I2, ', test ', I2, ', ratio = ',
528     $      G12.5 )
529 9998 FORMAT( ' N =', I5, ', NRHS=', I3, ', type ', I2, ', test(', I2,
530     $      ') = ', G12.5 )
531      RETURN
532*
533*     End of SCHKPT
534*
535      END
536