BLAS/SRC/dspr.f(3)

NAME
BLAS/SRC/dspr.f

SYNOPSIS

  Functions/Subroutines
subroutine dspr (uplo, n, alpha, x, incx, ap)
DSPR

Function/Subroutine Documentation

  subroutine dspr (character uplo, integer n, double precision alpha, double precision, dimension(*) x, integer incx, double precision, dimension(*) ap)

DSPR

Purpose:

     DSPR    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, 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.

    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 126 of file dspr.f.

Author

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