BLAS/SRC/dsyr.f(3)

NAME
BLAS/SRC/dsyr.f

SYNOPSIS

  Functions/Subroutines
subroutine dsyr (uplo, n, alpha, x, incx, a, lda)
DSYR

Function/Subroutine Documentation

  subroutine dsyr (character uplo, integer n, double precision alpha, double precision, dimension(*) x, integer incx, double precision, dimension(lda,*) a, integer lda)

DSYR

Purpose:

    !>
    !> DSYR   performs the symmetric rank 1 operation
    !>
    !>    A := alpha*x*x**T + A,
    !>
    !> where alpha is a real scalar, x is an n element vector and A is an
    !> n by n symmetric matrix.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>           On entry, UPLO specifies whether the upper or lower
    !>           triangular part of the array A is to be referenced as
    !>           follows:
    !>
    !>              UPLO = 'U' or 'u'   Only the upper triangular part of A
    !>                                  is to be referenced.
    !>
    !>              UPLO = 'L' or 'l'   Only the lower triangular part of A
    !>                                  is to be referenced.
    !>

    N

    !>          N is INTEGER
    !>           On entry, N specifies the order of the matrix A.
    !>           N must be at least zero.
    !>

    ALPHA

    !>          ALPHA is DOUBLE PRECISION.
    !>           On entry, ALPHA specifies the scalar alpha.
    !>

    X

    !>          X is DOUBLE PRECISION array, dimension at least
    !>           ( 1 + ( n - 1 )*abs( INCX ) ).
    !>           Before entry, the incremented array X must contain the n
    !>           element vector x.
    !>

    INCX

    !>          INCX is INTEGER
    !>           On entry, INCX specifies the increment for the elements of
    !>           X. INCX must not be zero.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension ( LDA, N )
    !>           Before entry with  UPLO = 'U' or 'u', the leading n by n
    !>           upper triangular part of the array A must contain the upper
    !>           triangular part of the symmetric matrix and the strictly
    !>           lower triangular part of A is not referenced. On exit, the
    !>           upper triangular part of the array A is overwritten by the
    !>           upper triangular part of the updated matrix.
    !>           Before entry with UPLO = 'L' or 'l', the leading n by n
    !>           lower triangular part of the array A must contain the lower
    !>           triangular part of the symmetric matrix and the strictly
    !>           upper triangular part of A is not referenced. On exit, the
    !>           lower triangular part of the array A is overwritten by the
    !>           lower triangular part of the updated matrix.
    !>

    LDA

    !>          LDA is INTEGER
    !>           On entry, LDA specifies the first dimension of A as declared
    !>           in the calling (sub) program. LDA must be at least
    !>           max( 1, n ).
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

    !>
    !>  Level 2 Blas routine.
    !>
    !>  -- Written on 22-October-1986.
    !>     Jack Dongarra, Argonne National Lab.
    !>     Jeremy Du Croz, Nag Central Office.
    !>     Sven Hammarling, Nag Central Office.
    !>     Richard Hanson, Sandia National Labs.
    !>

Definition at line 131 of file dsyr.f.

Author

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