SRC/cspr.f(3)

NAME
SRC/cspr.f

SYNOPSIS

  Functions/Subroutines
subroutine cspr (uplo, n, alpha, x, incx, ap)
CSPR performs the symmetrical rank-1 update of a complex symmetric packed matrix.

Function/Subroutine Documentation

  subroutine cspr (character uplo, integer n, complex alpha, complex, dimension( * ) x, integer incx, complex, dimension( * ) ap)

CSPR performs the symmetrical rank-1 update of a complex symmetric packed matrix.

Purpose:

    !>
    !> CSPR    performs the symmetric rank 1 operation
    !>
    !>    A := alpha*x*x**H + A,
    !>
    !> where alpha is a complex scalar, x is an n element vector and A is an
    !> n by n symmetric matrix, supplied in packed form.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>           On entry, UPLO specifies whether the upper or lower
    !>           triangular part of the matrix A is supplied in the packed
    !>           array AP as follows:
    !>
    !>              UPLO = 'U' or 'u'   The upper triangular part of A is
    !>                                  supplied in AP.
    !>
    !>              UPLO = 'L' or 'l'   The lower triangular part of A is
    !>                                  supplied in AP.
    !>
    !>           Unchanged on exit.
    !>

    N

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

    ALPHA

    !>          ALPHA is COMPLEX
    !>           On entry, ALPHA specifies the scalar alpha.
    !>           Unchanged on exit.
    !>

    X

    !>          X is COMPLEX array, dimension at least
    !>           ( 1 + ( N - 1 )*abs( INCX ) ).
    !>           Before entry, the incremented array X must contain the N-
    !>           element vector x.
    !>           Unchanged on exit.
    !>

    INCX

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

    AP

    !>          AP is COMPLEX array, dimension at least
    !>           ( ( N*( N + 1 ) )/2 ).
    !>           Before entry, with  UPLO = 'U' or 'u', the array AP must
    !>           contain the upper triangular part of the symmetric matrix
    !>           packed sequentially, column by column, so that AP( 1 )
    !>           contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 )
    !>           and a( 2, 2 ) respectively, and so on. On exit, the array
    !>           AP is overwritten by the upper triangular part of the
    !>           updated matrix.
    !>           Before entry, with UPLO = 'L' or 'l', the array AP must
    !>           contain the lower triangular part of the symmetric matrix
    !>           packed sequentially, column by column, so that AP( 1 )
    !>           contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 )
    !>           and a( 3, 1 ) respectively, and so on. On exit, the array
    !>           AP is overwritten by the lower triangular part of the
    !>           updated matrix.
    !>           Note that the imaginary parts of the diagonal elements need
    !>           not be set, they are assumed to be zero, and on exit they
    !>           are set to zero.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 131 of file cspr.f.

Author

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