BLAS/SRC/dspr2.f(3)        Library Functions Manual        BLAS/SRC/dspr2.f(3)

NAME
       BLAS/SRC/dspr2.f

SYNOPSIS
   Functions/Subroutines
       subroutine dspr2 (uplo, n, alpha, x, incx, y, incy, ap)
           DSPR2

Function/Subroutine Documentation
   subroutine dspr2 (character uplo, integer n, double precision alpha, double
       precision, dimension(*) x, integer incx, double precision, dimension(*)
       y, integer incy, double precision, dimension(*) ap)
       DSPR2

       Purpose:


           !>
           !> DSPR2  performs the symmetric rank 2 operation
           !>
           !>    A := alpha*x*y**T + alpha*y*x**T + A,
           !>
           !> where alpha is a scalar, x and y are n element vectors 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.
           !>

           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.
           !>

           Y

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

           INCY

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

           AP

           !>          AP is DOUBLE PRECISION 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.
           !>

       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 141 of file dspr2.f.

Author
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LAPACK                          Version 3.12.0             BLAS/SRC/dspr2.f(3)