clatme.f - Man Page

TESTING/MATGEN/clatme.f

Synopsis

Functions/Subroutines

subroutine clatme (n, dist, iseed, d, mode, cond, dmax, rsign, upper, sim, ds, modes, conds, kl, ku, anorm, a, lda, work, info)
CLATME

Function/Subroutine Documentation

subroutine clatme (integer n, character dist, integer, dimension( 4 ) iseed, complex, dimension( * ) d, integer mode, real cond, complex dmax, character rsign, character upper, character sim, real, dimension( * ) ds, integer modes, real conds, integer kl, integer ku, real anorm, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) work, integer info)

CLATME

Purpose:

    CLATME generates random non-symmetric square matrices with
    specified eigenvalues for testing LAPACK programs.

    CLATME operates by applying the following sequence of
    operations:

    1. Set the diagonal to D, where D may be input or
         computed according to MODE, COND, DMAX, and RSIGN
         as described below.

    2. If UPPER='T', the upper triangle of A is set to random values
         out of distribution DIST.

    3. If SIM='T', A is multiplied on the left by a random matrix
         X, whose singular values are specified by DS, MODES, and
         CONDS, and on the right by X inverse.

    4. If KL < N-1, the lower bandwidth is reduced to KL using
         Householder transformations.  If KU < N-1, the upper
         bandwidth is reduced to KU.

    5. If ANORM is not negative, the matrix is scaled to have
         maximum-element-norm ANORM.

    (Note: since the matrix cannot be reduced beyond Hessenberg form,
     no packing options are available.)
Parameters

N

          N is INTEGER
           The number of columns (or rows) of A. Not modified.

DIST

          DIST is CHARACTER*1
           On entry, DIST specifies the type of distribution to be used
           to generate the random eigen-/singular values, and on the
           upper triangle (see UPPER).
           'U' => UNIFORM( 0, 1 )  ( 'U' for uniform )
           'S' => UNIFORM( -1, 1 ) ( 'S' for symmetric )
           'N' => NORMAL( 0, 1 )   ( 'N' for normal )
           'D' => uniform on the complex disc |z| < 1.
           Not modified.

ISEED

          ISEED is INTEGER array, dimension ( 4 )
           On entry ISEED specifies the seed of the random number
           generator. They should lie between 0 and 4095 inclusive,
           and ISEED(4) should 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 CLATME
           to continue the same random number sequence.
           Changed on exit.

D

          D is COMPLEX array, dimension ( N )
           This array is used to specify the eigenvalues of A.  If
           MODE=0, then D is assumed to contain the eigenvalues
           otherwise they will be computed according to MODE, COND,
           DMAX, and RSIGN and placed in D.
           Modified if MODE is nonzero.

MODE

          MODE is INTEGER
           On entry this describes how the eigenvalues are to
           be specified:
           MODE = 0 means use D as input
           MODE = 1 sets D(1)=1 and D(2:N)=1.0/COND
           MODE = 2 sets D(1:N-1)=1 and D(N)=1.0/COND
           MODE = 3 sets D(I)=COND**(-(I-1)/(N-1))
           MODE = 4 sets D(i)=1 - (i-1)/(N-1)*(1 - 1/COND)
           MODE = 5 sets D to random numbers in the range
                    ( 1/COND , 1 ) such that their logarithms
                    are uniformly distributed.
           MODE = 6 set D to random numbers from same distribution
                    as the rest of the matrix.
           MODE < 0 has the same meaning as ABS(MODE), except that
              the order of the elements of D is reversed.
           Thus if MODE is between 1 and 4, D has entries ranging
              from 1 to 1/COND, if between -1 and -4, D has entries
              ranging from 1/COND to 1,
           Not modified.

COND

          COND is REAL
           On entry, this is used as described under MODE above.
           If used, it must be >= 1. Not modified.

DMAX

          DMAX is COMPLEX
           If MODE is neither -6, 0 nor 6, the contents of D, as
           computed according to MODE and COND, will be scaled by
           DMAX / max(abs(D(i))).  Note that DMAX need not be
           positive or real: if DMAX is negative or complex (or zero),
           D will be scaled by a negative or complex number (or zero).
           If RSIGN='F' then the largest (absolute) eigenvalue will be
           equal to DMAX.
           Not modified.

RSIGN

          RSIGN is CHARACTER*1
           If MODE is not 0, 6, or -6, and RSIGN='T', then the
           elements of D, as computed according to MODE and COND, will
           be multiplied by a random complex number from the unit
           circle |z| = 1.  If RSIGN='F', they will not be.  RSIGN may
           only have the values 'T' or 'F'.
           Not modified.

UPPER

          UPPER is CHARACTER*1
           If UPPER='T', then the elements of A above the diagonal
           will be set to random numbers out of DIST.  If UPPER='F',
           they will not.  UPPER may only have the values 'T' or 'F'.
           Not modified.

SIM

          SIM is CHARACTER*1
           If SIM='T', then A will be operated on by a 'similarity
           transform', i.e., multiplied on the left by a matrix X and
           on the right by X inverse.  X = U S V, where U and V are
           random unitary matrices and S is a (diagonal) matrix of
           singular values specified by DS, MODES, and CONDS.  If
           SIM='F', then A will not be transformed.
           Not modified.

DS

          DS is REAL array, dimension ( N )
           This array is used to specify the singular values of X,
           in the same way that D specifies the eigenvalues of A.
           If MODE=0, the DS contains the singular values, which
           may not be zero.
           Modified if MODE is nonzero.

MODES

          MODES is INTEGER

CONDS

          CONDS is REAL
           Similar to MODE and COND, but for specifying the diagonal
           of S.  MODES=-6 and +6 are not allowed (since they would
           result in randomly ill-conditioned eigenvalues.)

KL

          KL is INTEGER
           This specifies the lower bandwidth of the  matrix.  KL=1
           specifies upper Hessenberg form.  If KL is at least N-1,
           then A will have full lower bandwidth.
           Not modified.

KU

          KU is INTEGER
           This specifies the upper bandwidth of the  matrix.  KU=1
           specifies lower Hessenberg form.  If KU is at least N-1,
           then A will have full upper bandwidth; if KU and KL
           are both at least N-1, then A will be dense.  Only one of
           KU and KL may be less than N-1.
           Not modified.

ANORM

          ANORM is REAL
           If ANORM is not negative, then A will be scaled by a non-
           negative real number to make the maximum-element-norm of A
           to be ANORM.
           Not modified.

A

          A is COMPLEX array, dimension ( LDA, N )
           On exit A is the desired test matrix.
           Modified.

LDA

          LDA is INTEGER
           LDA specifies the first dimension of A as declared in the
           calling program.  LDA must be at least M.
           Not modified.

WORK

          WORK is COMPLEX array, dimension ( 3*N )
           Workspace.
           Modified.

INFO

          INFO is INTEGER
           Error code.  On exit, INFO will be set to one of the
           following values:
             0 => normal return
            -1 => N negative
            -2 => DIST illegal string
            -5 => MODE not in range -6 to 6
            -6 => COND less than 1.0, and MODE neither -6, 0 nor 6
            -9 => RSIGN is not 'T' or 'F'
           -10 => UPPER is not 'T' or 'F'
           -11 => SIM   is not 'T' or 'F'
           -12 => MODES=0 and DS has a zero singular value.
           -13 => MODES is not in the range -5 to 5.
           -14 => MODES is nonzero and CONDS is less than 1.
           -15 => KL is less than 1.
           -16 => KU is less than 1, or KL and KU are both less than
                  N-1.
           -19 => LDA is less than M.
            1  => Error return from CLATM1 (computing D)
            2  => Cannot scale to DMAX (max. eigenvalue is 0)
            3  => Error return from SLATM1 (computing DS)
            4  => Error return from CLARGE
            5  => Zero singular value from SLATM1.
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 296 of file clatme.f.

Author

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Referenced By

The man page clatme(3) is an alias of clatme.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK