TESTING/MATGEN/slagsy.f(3)

NAME
TESTING/MATGEN/slagsy.f

SYNOPSIS

  Functions/Subroutines
subroutine slagsy (n, k, d, a, lda, iseed, work, info)
SLAGSY

Function/Subroutine Documentation

  subroutine slagsy (integer n, integer k, real, dimension( * ) d, real, dimension( lda, * ) a, integer lda, integer, dimension( 4 ) iseed, real, dimension( * ) work, integer info)

SLAGSY

Purpose:

    !>
    !> SLAGSY generates a real symmetric matrix A, by pre- and post-
    !> multiplying a real diagonal matrix D with a random orthogonal matrix:
    !> A = U*D*U'. The semi-bandwidth may then be reduced to k by additional
    !> orthogonal transformations.
    !>

Parameters
    N

    !>          N is INTEGER
    !>          The order of the matrix A.  N >= 0.
    !>

    K

    !>          K is INTEGER
    !>          The number of nonzero subdiagonals within the band of A.
    !>          0 <= K <= N-1.
    !>

    D

    !>          D is REAL array, dimension (N)
    !>          The diagonal elements of the diagonal matrix D.
    !>

    A

    !>          A is REAL array, dimension (LDA,N)
    !>          The generated n by n symmetric matrix A (the full matrix is
    !>          stored).
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of the array A.  LDA >= N.
    !>

    ISEED

    !>          ISEED is INTEGER array, dimension (4)
    !>          On entry, the seed of the random number generator; the array
    !>          elements must be between 0 and 4095, and ISEED(4) must be
    !>          odd.
    !>          On exit, the seed is updated.
    !>

    WORK

    !>          WORK is REAL array, dimension (2*N)
    !>

    INFO

    !>          INFO is INTEGER
    !>          = 0: successful exit
    !>          < 0: if INFO = -i, the i-th argument had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 100 of file slagsy.f.

Author

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