sdrgev.f

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*          ( ALPHAR(k)+ALPHAI(k)*i ) / BETA(k) is the k-th
*          generalized eigenvalue of A and B.
*
*  ALPHR1  (workspace) REAL array, dimension (max(NN))
*  ALPHI1  (workspace) REAL array, dimension (max(NN))
*  BETA1   (workspace) REAL array, dimension (max(NN))
*          Like ALPHAR, ALPHAI, BETA, these arrays contain the
*          eigenvalues of A and B, but those computed when SGGEV only
*          computes a partial eigendecomposition, i.e. not the
*          eigenvalues and left and right eigenvectors.
*
*  WORK    (workspace) REAL array, dimension (LWORK)
*
*  LWORK   (input) INTEGER
*          The number of entries in WORK.  LWORK >= MAX( 8*N, N*(N+1) ).
*
*  RESULT  (output) REAL array, dimension (2)
*          The values computed by the tests described above.
*          The values are currently limited to 1/ulp, to avoid overflow.
*
*  INFO    (output) INTEGER
*          = 0:  successful exit
*          < 0:  if INFO = -i, the i-th argument had an illegal value.
*          > 0:  A routine returned an error code.  INFO is the
*                absolute value of the INFO value returned.
*
*  =====================================================================
*
*     .. Parameters ..
      REAL               ZERO, ONE
      PARAMETER          ( ZERO = 0.0E+0, ONE = 1.0E+0 )
      INTEGER            MAXTYP
      PARAMETER          ( MAXTYP = 26 )
*     ..
*     .. Local Scalars ..
      LOGICAL            BADNN
      INTEGER            I, IADD, IERR, IN, J, JC, JR, JSIZE, JTYPE,
     $                   MAXWRK, MINWRK, MTYPES, N, N1, NERRS, NMATS,
     $                   NMAX, NTESTT
      REAL               SAFMAX, SAFMIN, ULP, ULPINV
*     ..
*     .. Local Arrays ..
      INTEGER            IASIGN( MAXTYP ), IBSIGN( MAXTYP ),
     $                   IOLDSD( 4 ), KADD( 6 ), KAMAGN( MAXTYP ),
     $                   KATYPE( MAXTYP ), KAZERO( MAXTYP ),
     $                   KBMAGN( MAXTYP ), KBTYPE( MAXTYP ),
     $                   KBZERO( MAXTYP ), KCLASS( MAXTYP ),
     $                   KTRIAN( MAXTYP ), KZ1( 6 ), KZ2( 6 )
      REAL               RMAGN( 0: 3 )
*     ..
*     .. External Functions ..
      INTEGER            ILAENV
      REAL               SLAMCH, SLARND
      EXTERNAL           ILAENV, SLAMCH, SLARND
*     ..
*     .. External Subroutines ..
      EXTERNAL           ALASVM, SGET52, SGGEV, SLABAD, SLACPY, SLARFG,
     $                   SLASET, SLATM4, SORM2R, XERBLA
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          ABS, MAX, MIN, REAL, SIGN
*     ..
*     .. Data statements ..
      DATA               KCLASS / 15*1, 10*2, 1*3 /
      DATA               KZ1 / 0, 1, 2, 1, 3, 3 /
      DATA               KZ2 / 0, 0, 1, 2, 1, 1 /
      DATA               KADD / 0, 0, 0, 0, 3, 2 /
      DATA               KATYPE / 0, 1, 0, 1, 2, 3, 4, 1, 4, 4, 1, 1, 4,
     $                   4, 4, 2, 4, 5, 8, 7, 9, 4*4, 0 /
      DATA               KBTYPE / 0, 0, 1, 1, 2, -3, 1, 4, 1, 1, 4, 4,
     $                   1, 1, -4, 2, -4, 8*8, 0 /
      DATA               KAZERO / 6*1, 2, 1, 2*2, 2*1, 2*2, 3, 1, 3,
     $                   4*5, 4*3, 1 /
      DATA               KBZERO / 6*1, 1, 2, 2*1, 2*2, 2*1, 4, 1, 4,
     $                   4*6, 4*4, 1 /
      DATA               KAMAGN / 8*1, 2, 3, 2, 3, 2, 3, 7*1, 2, 3, 3,
     $                   2, 1 /
      DATA               KBMAGN / 8*1, 3, 2, 3, 2, 2, 3, 7*1, 3, 2, 3,
     $                   2, 1 /
      DATA               KTRIAN / 16*0, 10*1 /
      DATA               IASIGN / 6*0, 2, 0, 2*2, 2*0, 3*2, 0, 2, 3*0,
     $                   5*2, 0 /
      DATA               IBSIGN / 7*0, 2, 2*0, 2*2, 2*0, 2, 0, 2, 9*0 /
*     ..
*     .. Executable Statements ..
*
*     Check for errors
*
      INFO = 0
*
      BADNN = .FALSE.
      NMAX = 1
      DO 10 J = 1, NSIZES
         NMAX = MAX( NMAX, NN( J ) )
         IF( NN( J ).LT.0 )
     $      BADNN = .TRUE.
   10 CONTINUE
*
      IF( NSIZES.LT.0 ) THEN
         INFO = -1
      ELSE IF( BADNN ) THEN
         INFO = -2
      ELSE IF( NTYPES.LT.0 ) THEN
         INFO = -3
      ELSE IF( THRESH.LT.ZERO ) THEN
         INFO = -6
      ELSE IF( LDA.LE.1 .OR. LDA.LT.NMAX ) THEN
         INFO = -9
      ELSE IF( LDQ.LE.1 .OR. LDQ.LT.NMAX ) THEN
         INFO = -14
      ELSE IF( LDQE.LE.1 .OR. LDQE.LT.NMAX ) THEN
         INFO = -17
      END IF
*
*     Compute workspace
*      (Note: Comments in the code beginning "Workspace:" describe the
*       minimal amount of workspace needed at that point in the code,
*       as well as the preferred amount for good performance.
*       NB refers to the optimal block size for the immediately
*       following subroutine, as returned by ILAENV.
*
      MINWRK = 1
      IF( INFO.EQ.0 .AND. LWORK.GE.1 ) THEN
         MINWRK = MAX( 1, 8*NMAX, NMAX*( NMAX+1 ) )
         MAXWRK = 7*NMAX + NMAX*ILAENV( 1, 'SGEQRF', ' ', NMAX, 1, NMAX,
     $            0 )
         MAXWRK = MAX( MAXWRK, NMAX*( NMAX+1 ) )
         WORK( 1 ) = MAXWRK
      END IF
*
      IF( LWORK.LT.MINWRK )
     $   INFO = -25
*
      IF( INFO.NE.0 ) THEN
         CALL XERBLA( 'SDRGEV', -INFO )
         RETURN
      END IF
*
*     Quick return if possible
*
      IF( NSIZES.EQ.0 .OR. NTYPES.EQ.0 )
     $   RETURN
*
      SAFMIN = SLAMCH( 'Safe minimum' )
      ULP = SLAMCH( 'Epsilon' )*SLAMCH( 'Base' )
      SAFMIN = SAFMIN / ULP
      SAFMAX = ONE / SAFMIN
      CALL SLABAD( SAFMIN, SAFMAX )
      ULPINV = ONE / ULP
*
*     The values RMAGN(2:3) depend on N, see below.
*
      RMAGN( 0 ) = ZERO
      RMAGN( 1 ) = ONE
*
*     Loop over sizes, types
*
      NTESTT = 0
      NERRS = 0
      NMATS = 0
*
      DO 220 JSIZE = 1, NSIZES
         N = NN( JSIZE )
         N1 = MAX( 1, N )
         RMAGN( 2 ) = SAFMAX*ULP / REAL( N1 )
         RMAGN( 3 ) = SAFMIN*ULPINV*N1
*
         IF( NSIZES.NE.1 ) THEN
            MTYPES = MIN( MAXTYP, NTYPES )
         ELSE
            MTYPES = MIN( MAXTYP+1, NTYPES )
         END IF
*
         DO 210 JTYPE = 1, MTYPES
            IF( .NOT.DOTYPE( JTYPE ) )
     $         GO TO 210
            NMATS = NMATS + 1
*
*           Save ISEED in case of an error.
*
            DO 20 J = 1, 4
               IOLDSD( J ) = ISEED( J )
   20       CONTINUE
*
*           Generate test matrices A and B
*
*           Description of control parameters:
*
*           KCLASS: =1 means w/o rotation, =2 means w/ rotation,
*                   =3 means random.
*           KATYPE: the "type" to be passed to SLATM4 for computing A.
*           KAZERO: the pattern of zeros on the diagonal for A:
*                   =1: ( xxx ), =2: (0, xxx ) =3: ( 0, 0, xxx, 0 ),
*                   =4: ( 0, xxx, 0, 0 ), =5: ( 0, 0, 1, xxx, 0 ),
*                   =6: ( 0, 1, 0, xxx, 0 ).  (xxx means a string of
*                   non-zero entries.)
*           KAMAGN: the magnitude of the matrix: =0: zero, =1: O(1),
*                   =2: large, =3: small.
*           IASIGN: 1 if the diagonal elements of A are to be
*                   multiplied by a random magnitude 1 number, =2 if
*                   randomly chosen diagonal blocks are to be rotated
*                   to form 2x2 blocks.
*           KBTYPE, KBZERO, KBMAGN, IBSIGN: the same, but for B.
*           KTRIAN: =0: don't fill in the upper triangle, =1: do.
*           KZ1, KZ2, KADD: used to implement KAZERO and KBZERO.
*           RMAGN: used to implement KAMAGN and KBMAGN.
*
            IF( MTYPES.GT.MAXTYP )
     $         GO TO 100
            IERR = 0
            IF( KCLASS( JTYPE ).LT.3 ) THEN
*
*              Generate A (w/o rotation)
*
               IF( ABS( KATYPE( JTYPE ) ).EQ.3 ) THEN
                  IN = 2*( ( N-1 ) / 2 ) + 1
                  IF( IN.NE.N )
     $               CALL SLASET( 'Full', N, N, ZERO, ZERO, A, LDA )
               ELSE
                  IN = N
               END IF
               CALL SLATM4( KATYPE( JTYPE ), IN, KZ1( KAZERO( JTYPE ) ),
     $                      KZ2( KAZERO( JTYPE ) ), IASIGN( JTYPE ),
     $                      RMAGN( KAMAGN( JTYPE ) ), ULP,
     $                      RMAGN( KTRIAN( JTYPE )*KAMAGN( JTYPE ) ), 2,
     $                      ISEED, A, LDA )
               IADD = KADD( KAZERO( JTYPE ) )
               IF( IADD.GT.0 .AND. IADD.LE.N )
     $            A( IADD, IADD ) = ONE
*
*              Generate B (w/o rotation)
*
               IF( ABS( KBTYPE( JTYPE ) ).EQ.3 ) THEN
                  IN = 2*( ( N-1 ) / 2 ) + 1
                  IF( IN.NE.N )
     $               CALL SLASET( 'Full', N, N, ZERO, ZERO, B, LDA )
               ELSE
                  IN = N
               END IF
               CALL SLATM4( KBTYPE( JTYPE ), IN, KZ1( KBZERO( JTYPE ) ),
     $                      KZ2( KBZERO( JTYPE ) ), IBSIGN( JTYPE ),
     $                      RMAGN( KBMAGN( JTYPE ) ), ONE,
     $                      RMAGN( KTRIAN( JTYPE )*KBMAGN( JTYPE ) ), 2,
     $                      ISEED, B, LDA )
               IADD = KADD( KBZERO( JTYPE ) )
               IF( IADD.NE.0 .AND. IADD.LE.N )
     $            B( IADD, IADD ) = ONE
*
               IF( KCLASS( JTYPE ).EQ.2 .AND. N.GT.0 ) THEN
*
*                 Include rotations
*
*                 Generate Q, Z as Householder transformations times
*                 a diagonal matrix.
*
                  DO 40 JC = 1, N - 1
                     DO 30 JR = JC, N
                        Q( JR, JC ) = SLARND( 3, ISEED )
                        Z( JR, JC ) = SLARND( 3, ISEED )
   30                CONTINUE
                     CALL SLARFG( N+1-JC, Q( JC, JC ), Q( JC+1, JC ), 1,
     $                            WORK( JC ) )
                     WORK( 2*N+JC ) = SIGN( ONE, Q( JC, JC ) )
                     Q( JC, JC ) = ONE
                     CALL SLARFG( N+1-JC, Z( JC, JC ), Z( JC+1, JC ), 1,
     $                            WORK( N+JC ) )
                     WORK( 3*N+JC ) = SIGN( ONE, Z( JC, JC ) )
                     Z( JC, JC ) = ONE
   40             CONTINUE