TESTING/MATGEN/claror.f(3)

NAME
TESTING/MATGEN/claror.f

SYNOPSIS

  Functions/Subroutines
subroutine claror (side, init, m, n, a, lda, iseed, x, info)
CLAROR

Function/Subroutine Documentation

  subroutine claror (character side, character init, integer m, integer n, complex, dimension( lda, * ) a, integer lda, integer, dimension( 4 ) iseed, complex, dimension( * ) x, integer info)

CLAROR

Purpose:

        CLAROR pre- or post-multiplies an M by N matrix A by a random
        unitary matrix U, overwriting A. A may optionally be
        initialized to the identity matrix before multiplying by U.
        U is generated using the method of G.W. Stewart
        ( SIAM J. Numer. Anal. 17, 1980, pp. 403-409 ).
        (BLAS-2 version)

Parameters
    SIDE

              SIDE is CHARACTER*1
               SIDE specifies whether A is multiplied on the left or right
               by U.
           SIDE = 'L'   Multiply A on the left (premultiply) by U
           SIDE = 'R'   Multiply A on the right (postmultiply) by UC>       SIDE = 'C'   Multiply A on the left by U and the right by UC>       SIDE = 'T'   Multiply A on the left by U and the right by U'
               Not modified.

    INIT

              INIT is CHARACTER*1
               INIT specifies whether or not A should be initialized to
               the identity matrix.
                  INIT = 'I'   Initialize A to (a section of) the
                               identity matrix before applying U.
                  INIT = 'N'   No initialization.  Apply U to the
                               input matrix A.
               INIT = 'I' may be used to generate square (i.e., unitary)
               or rectangular orthogonal matrices (orthogonality being
               in the sense of CDOTC):
               For square matrices, M=N, and SIDE many be either 'L' or
               'R'; the rows will be orthogonal to each other, as will the
               columns.
               For rectangular matrices where M < N, SIDE = 'R' will
               produce a dense matrix whose rows will be orthogonal and
               whose columns will not, while SIDE = 'L' will produce a
               matrix whose rows will be orthogonal, and whose first M
               columns will be orthogonal, the remaining columns being
               zero.
               For matrices where M > N, just use the previous
               explanation, interchanging 'L' and 'R' and 'rows' and
               'columns'.
               Not modified.

    M

              M is INTEGER
               Number of rows of A. Not modified.

    N

              N is INTEGER
               Number of columns of A. Not modified.

    A

              A is COMPLEX array, dimension ( LDA, N )
               Input and output array. Overwritten by U A ( if SIDE = 'L' )
               or by A U ( if SIDE = 'R' )
               or by U A U* ( if SIDE = 'C')
               or by U A U' ( if SIDE = 'T') on exit.

    LDA

              LDA is INTEGER
               Leading dimension of A. Must be at least MAX ( 1, M ).
               Not modified.

    ISEED

              ISEED is 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 CLAROR to continue the same random number
               sequence.
               Modified.

    X

              X is COMPLEX array, dimension ( 3*MAX( M, N ) )
               Workspace. Of length:
                   2*M + N if SIDE = 'L',
                   2*N + M if SIDE = 'R',
                   3*N     if SIDE = 'C' or 'T'.
               Modified.

    INFO

              INFO is INTEGER
               An error flag.  It is set to:
                0  if no error.
                1  if CLARND returned a bad random number (installation
                   problem)
               -1  if SIDE is not L, R, C, or T.
               -3  if M is negative.
               -4  if N is negative or if SIDE is C or T and N is not equal
                   to M.
               -6  if LDA is less than M.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 157 of file claror.f.

Author

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