schkgg.f

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      SUBROUTINE SCHKGG( NSIZES, NN, NTYPES, DOTYPE, ISEED, THRESH,
     $                   TSTDIF, THRSHN, NOUNIT, A, LDA, B, H, T, S1,
     $                   S2, P1, P2, U, LDU, V, Q, Z, ALPHR1, ALPHI1,
     $                   BETA1, ALPHR3, ALPHI3, BETA3, EVECTL, EVECTR,
     $                   WORK, LWORK, LLWORK, RESULT, INFO )
*
*  -- LAPACK test routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
      LOGICAL            TSTDIF
      INTEGER            INFO, LDA, LDU, LWORK, NOUNIT, NSIZES, NTYPES
      REAL               THRESH, THRSHN
*     ..
*     .. Array Arguments ..
      LOGICAL            DOTYPE( * ), LLWORK( * )
      INTEGER            ISEED( 4 ), NN( * )
      REAL               A( LDA, * ), ALPHI1( * ), ALPHI3( * ),
     $                   ALPHR1( * ), ALPHR3( * ), B( LDA, * ),
     $                   BETA1( * ), BETA3( * ), EVECTL( LDU, * ),
     $                   EVECTR( LDU, * ), H( LDA, * ), P1( LDA, * ),
     $                   P2( LDA, * ), Q( LDU, * ), RESULT( 15 ),
     $                   S1( LDA, * ), S2( LDA, * ), T( LDA, * ),
     $                   U( LDU, * ), V( LDU, * ), WORK( * ),
     $                   Z( LDU, * )
*     ..
*
*  Purpose
*  =======
*
*  SCHKGG  checks the nonsymmetric generalized eigenvalue problem
*  routines.
*                                 T          T        T
*  SGGHRD factors A and B as U H V  and U T V , where   means
*  transpose, H is hessenberg, T is triangular and U and V are
*  orthogonal.
*                                  T          T
*  SHGEQZ factors H and T as  Q S Z  and Q P Z , where P is upper
*  triangular, S is in generalized Schur form (block upper triangular,
*  with 1x1 and 2x2 blocks on the diagonal, the 2x2 blocks
*  corresponding to complex conjugate pairs of generalized
*  eigenvalues), and Q and Z are orthogonal.  It also computes the
*  generalized eigenvalues (alpha(1),beta(1)),...,(alpha(n),beta(n)),
*  where alpha(j)=S(j,j) and beta(j)=P(j,j) -- thus,
*  w(j) = alpha(j)/beta(j) is a root of the generalized eigenvalue
*  problem
*
*      det( A - w(j) B ) = 0
*
*  and m(j) = beta(j)/alpha(j) is a root of the essentially equivalent
*  problem
*
*      det( m(j) A - B ) = 0
*
*  STGEVC computes the matrix L of left eigenvectors and the matrix R
*  of right eigenvectors for the matrix pair ( S, P ).  In the
*  description below,  l and r are left and right eigenvectors
*  corresponding to the generalized eigenvalues (alpha,beta).
*
*  When SCHKGG is called, a number of matrix "sizes" ("n's") and a
*  number of matrix "types" are specified.  For each size ("n")
*  and each type of matrix, one matrix will be generated and used
*  to test the nonsymmetric eigenroutines.  For each matrix, 15
*  tests will be performed.  The first twelve "test ratios" should be
*  small -- O(1).  They will be compared with the threshhold THRESH:
*
*                   T
*  (1)   | A - U H V  | / ( |A| n ulp )
*
*                   T
*  (2)   | B - U T V  | / ( |B| n ulp )
*
*                T
*  (3)   | I - UU  | / ( n ulp )
*
*                T
*  (4)   | I - VV  | / ( n ulp )
*
*                   T
*  (5)   | H - Q S Z  | / ( |H| n ulp )
*
*                   T
*  (6)   | T - Q P Z  | / ( |T| n ulp )
*
*                T
*  (7)   | I - QQ  | / ( n ulp )
*
*                T
*  (8)   | I - ZZ  | / ( n ulp )
*
*  (9)   max over all left eigenvalue/-vector pairs (beta/alpha,l) of
*
*     | l**H * (beta S - alpha P) | / ( ulp max( |beta S|, |alpha P| ) )
*
*  (10)  max over all left eigenvalue/-vector pairs (beta/alpha,l') of
*                            T
*    | l'**H * (beta H - alpha T) | / ( ulp max( |beta H|, |alpha T| ) )
*
*        where the eigenvectors l' are the result of passing Q to
*        STGEVC and back transforming (HOWMNY='B').
*
*  (11)  max over all right eigenvalue/-vector pairs (beta/alpha,r) of
*
*        | (beta S - alpha T) r | / ( ulp max( |beta S|, |alpha T| ) )
*
*  (12)  max over all right eigenvalue/-vector pairs (beta/alpha,r') of
*
*        | (beta H - alpha T) r' | / ( ulp max( |beta H|, |alpha T| ) )
*
*        where the eigenvectors r' are the result of passing Z to
*        STGEVC and back transforming (HOWMNY='B').
*
*  The last three test ratios will usually be small, but there is no
*  mathematical requirement that they be so.  They are therefore
*  compared with THRESH only if TSTDIF is .TRUE.
*
*  (13)  | S(Q,Z computed) - S(Q,Z not computed) | / ( |S| ulp )
*
*  (14)  | P(Q,Z computed) - P(Q,Z not computed) | / ( |P| ulp )
*
*  (15)  max( |alpha(Q,Z computed) - alpha(Q,Z not computed)|/|S| ,
*             |beta(Q,Z computed) - beta(Q,Z not computed)|/|P| ) / ulp
*
*  In addition, the normalization of L and R are checked, and compared
*  with the threshhold THRSHN.
*
*  Test Matrices
*  ---- --------
*
*  The sizes of the test matrices are specified by an array
*  NN(1:NSIZES); the value of each element NN(j) specifies one size.
*  The "types" are specified by a logical array DOTYPE( 1:NTYPES ); if
*  DOTYPE(j) is .TRUE., then matrix type "j" will be generated.
*  Currently, the list of possible types is:
*
*  (1)  ( 0, 0 )         (a pair of zero matrices)
*
*  (2)  ( I, 0 )         (an identity and a zero matrix)
*
*  (3)  ( 0, I )         (an identity and a zero matrix)
*
*  (4)  ( I, I )         (a pair of identity matrices)
*
*          t   t
*  (5)  ( J , J  )       (a pair of transposed Jordan blocks)
*
*                                      t                ( I   0  )
*  (6)  ( X, Y )         where  X = ( J   0  )  and Y = (      t )
*                                   ( 0   I  )          ( 0   J  )
*                        and I is a k x k identity and J a (k+1)x(k+1)
*                        Jordan block; k=(N-1)/2
*
*  (7)  ( D, I )         where D is diag( 0, 1,..., N-1 ) (a diagonal
*                        matrix with those diagonal entries.)
*  (8)  ( I, D )
*
*  (9)  ( big*D, small*I ) where "big" is near overflow and small=1/big
*
*  (10) ( small*D, big*I )
*
*  (11) ( big*I, small*D )
*
*  (12) ( small*I, big*D )
*
*  (13) ( big*D, big*I )
*
*  (14) ( small*D, small*I )
*
*  (15) ( D1, D2 )        where D1 is diag( 0, 0, 1, ..., N-3, 0 ) and
*                         D2 is diag( 0, N-3, N-4,..., 1, 0, 0 )
*            t   t
*  (16) U ( J , J ) V     where U and V are random orthogonal matrices.
*
*  (17) U ( T1, T2 ) V    where T1 and T2 are upper triangular matrices
*                         with random O(1) entries above the diagonal
*                         and diagonal entries diag(T1) =
*                         ( 0, 0, 1, ..., N-3, 0 ) and diag(T2) =
*                         ( 0, N-3, N-4,..., 1, 0, 0 )
*
*  (18) U ( T1, T2 ) V    diag(T1) = ( 0, 0, 1, 1, s, ..., s, 0 )
*                         diag(T2) = ( 0, 1, 0, 1,..., 1, 0 )
*                         s = machine precision.
*
*  (19) U ( T1, T2 ) V    diag(T1)=( 0,0,1,1, 1-d, ..., 1-(N-5)*d=s, 0 )
*                         diag(T2) = ( 0, 1, 0, 1, ..., 1, 0 )
*
*                                                         N-5
*  (20) U ( T1, T2 ) V    diag(T1)=( 0, 0, 1, 1, a, ..., a   =s, 0 )
*                         diag(T2) = ( 0, 1, 0, 1, ..., 1, 0, 0 )
*
*  (21) U ( T1, T2 ) V    diag(T1)=( 0, 0, 1, r1, r2, ..., r(N-4), 0 )
*                         diag(T2) = ( 0, 1, 0, 1, ..., 1, 0, 0 )
*                         where r1,..., r(N-4) are random.
*
*  (22) U ( big*T1, small*T2 ) V    diag(T1) = ( 0, 0, 1, ..., N-3, 0 )
*                                   diag(T2) = ( 0, 1, ..., 1, 0, 0 )
*
*  (23) U ( small*T1, big*T2 ) V    diag(T1) = ( 0, 0, 1, ..., N-3, 0 )
*                                   diag(T2) = ( 0, 1, ..., 1, 0, 0 )
*
*  (24) U ( small*T1, small*T2 ) V  diag(T1) = ( 0, 0, 1, ..., N-3, 0 )
*                                   diag(T2) = ( 0, 1, ..., 1, 0, 0 )
*
*  (25) U ( big*T1, big*T2 ) V      diag(T1) = ( 0, 0, 1, ..., N-3, 0 )
*                                   diag(T2) = ( 0, 1, ..., 1, 0, 0 )
*
*  (26) U ( T1, T2 ) V     where T1 and T2 are random upper-triangular
*                          matrices.
*
*  Arguments
*  =========
*
*  NSIZES  (input) INTEGER
*          The number of sizes of matrices to use.  If it is zero,
*          SCHKGG does nothing.  It must be at least zero.
*
*  NN      (input) INTEGER array, dimension (NSIZES)
*          An array containing the sizes to be used for the matrices.
*          Zero values will be skipped.  The values must be at least
*          zero.
*
*  NTYPES  (input) INTEGER
*          The number of elements in DOTYPE.   If it is zero, SCHKGG
*          does nothing.  It must be at least zero.  If it is MAXTYP+1
*          and NSIZES is 1, then an additional type, MAXTYP+1 is
*          defined, which is to use whatever matrix is in A.  This
*          is only useful if DOTYPE(1:MAXTYP) is .FALSE. and
*          DOTYPE(MAXTYP+1) is .TRUE. .
*
*  DOTYPE  (input) LOGICAL array, dimension (NTYPES)
*          If DOTYPE(j) is .TRUE., then for each size in NN a
*          matrix of that size and of type j will be generated.
*          If NTYPES is smaller than the maximum number of types
*          defined (PARAMETER MAXTYP), then types NTYPES+1 through
*          MAXTYP will not be generated.  If NTYPES is larger
*          than MAXTYP, DOTYPE(MAXTYP+1) through DOTYPE(NTYPES)
*          will be ignored.
*
*  ISEED   (input/output) INTEGER array, dimension (4)
*          On entry ISEED specifies the seed of the random number
*          generator. The array elements should be between 0 and 4095;
*          if not they will be reduced mod 4096.  Also, ISEED(4) must
*          be odd.  The random number generator uses a linear
*          congruential sequence limited to small integers, and so
*          should produce machine independent random numbers. The
*          values of ISEED are changed on exit, and can be used in the
*          next call to SCHKGG to continue the same random number
*          sequence.
*
*  THRESH  (input) REAL
*          A test will count as "failed" if the "error", computed as
*          described above, exceeds THRESH.  Note that the error is
*          scaled to be O(1), so THRESH should be a reasonably small
*          multiple of 1, e.g., 10 or 100.  In particular, it should
*          not depend on the precision (single vs. double) or the size
*          of the matrix.  It must be at least zero.
*
*  TSTDIF  (input) LOGICAL
*          Specifies whether test ratios 13-15 will be computed and
*          compared with THRESH.
*          = .FALSE.: Only test ratios 1-12 will be computed and tested.
*                     Ratios 13-15 will be set to zero.
*          = .TRUE.:  All the test ratios 1-15 will be computed and
*                     tested.
*
*  THRSHN  (input) REAL
*          Threshhold for reporting eigenvector normalization error.
*          If the normalization of any eigenvector differs from 1 by
*          more than THRSHN*ulp, then a special error message will be
*          printed.  (This is handled separately from the other tests,
*          since only a compiler or programming error should cause an
*          error message, at least if THRSHN is at least 5--10.)
*
*  NOUNIT  (input) INTEGER
*          The FORTRAN unit number for printing out error messages
*          (e.g., if a routine returns IINFO not equal to 0.)
*
*  A       (input/workspace) REAL array, dimension
*                            (LDA, max(NN))
*          Used to hold the original A matrix.  Used as input only
*          if NTYPES=MAXTYP+1, DOTYPE(1:MAXTYP)=.FALSE., and
*          DOTYPE(MAXTYP+1)=.TRUE.
*
*  LDA     (input) INTEGER
*          The leading dimension of A, B, H, T, S1, P1, S2, and P2.
*          It must be at least 1 and at least max( NN ).
*
*  B       (input/workspace) REAL array, dimension
*                            (LDA, max(NN))
*          Used to hold the original B matrix.  Used as input only
*          if NTYPES=MAXTYP+1, DOTYPE(1:MAXTYP)=.FALSE., and
*          DOTYPE(MAXTYP+1)=.TRUE.
*
*  H       (workspace) REAL array, dimension (LDA, max(NN))
*          The upper Hessenberg matrix computed from A by SGGHRD.
*
*  T       (workspace) REAL array, dimension (LDA, max(NN))
*          The upper triangular matrix computed from B by SGGHRD.
*
*  S1      (workspace) REAL array, dimension (LDA, max(NN))
*          The Schur (block upper triangular) matrix computed from H by
*          SHGEQZ when Q and Z are also computed.
*
*  S2      (workspace) REAL array, dimension (LDA, max(NN))
*          The Schur (block upper triangular) matrix computed from H by
*          SHGEQZ when Q and Z are not computed.
*
*  P1      (workspace) REAL array, dimension (LDA, max(NN))
*          The upper triangular matrix computed from T by SHGEQZ
*          when Q and Z are also computed.
*
*  P2      (workspace) REAL array, dimension (LDA, max(NN))
*          The upper triangular matrix computed from T by SHGEQZ
*          when Q and Z are not computed.
*
*  U       (workspace) REAL array, dimension (LDU, max(NN))
*          The (left) orthogonal matrix computed by SGGHRD.
*
*  LDU     (input) INTEGER
*          The leading dimension of U, V, Q, Z, EVECTL, and EVECTR.  It
*          must be at least 1 and at least max( NN ).
*
*  V       (workspace) REAL array, dimension (LDU, max(NN))
*          The (right) orthogonal matrix computed by SGGHRD.
*
*  Q       (workspace) REAL array, dimension (LDU, max(NN))
*          The (left) orthogonal matrix computed by SHGEQZ.
*
*  Z       (workspace) REAL array, dimension (LDU, max(NN))
*          The (left) orthogonal matrix computed by SHGEQZ.
*
*  ALPHR1  (workspace) REAL array, dimension (max(NN))
*  ALPHI1  (workspace) REAL array, dimension (max(NN))
*  BETA1   (workspace) REAL array, dimension (max(NN))
*
*          The generalized eigenvalues of (A,B) computed by SHGEQZ
*          when Q, Z, and the full Schur matrices are computed.
*          On exit, ( ALPHR1(k)+ALPHI1(k)*i ) / BETA1(k) is the k-th
*          generalized eigenvalue of the matrices in A and B.
*
*  ALPHR3  (workspace) REAL array, dimension (max(NN))
*  ALPHI3  (workspace) REAL array, dimension (max(NN))
*  BETA3   (workspace) REAL array, dimension (max(NN))
*
*  EVECTL  (workspace) REAL array, dimension (LDU, max(NN))
*          The (block lower triangular) left eigenvector matrix for
*          the matrices in S1 and P1.  (See STGEVC for the format.)
*
*  EVECTR  (workspace) REAL array, dimension (LDU, max(NN))
*          The (block upper triangular) right eigenvector matrix for
*          the matrices in S1 and P1.  (See STGEVC for the format.)
*
*  WORK    (workspace) REAL array, dimension (LWORK)
*
*  LWORK   (input) INTEGER
*          The number of entries in WORK.  This must be at least
*          max( 2 * N**2, 6*N, 1 ), for all N=NN(j).
*
*  LLWORK  (workspace) LOGICAL array, dimension (max(NN))
*

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