dspmv.f man page

dspmv.f —

Synopsis

Functions/Subroutines

subroutine dspmv (UPLO, N, ALPHA, AP, X, INCX, BETA, Y, INCY)
DSPMV

Function/Subroutine Documentation

subroutine dspmv (characterUPLO, integerN, double precisionALPHA, double precision, dimension(*)AP, double precision, dimension(*)X, integerINCX, double precisionBETA, double precision, dimension(*)Y, integerINCY)

DSPMV Purpose:

DSPMV  performs the matrix-vector operation

   y := alpha*A*x + beta*y,

where alpha and beta are scalars, 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.

AP

AP is DOUBLE PRECISION array of 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.
 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.

X

X is DOUBLE PRECISION array of 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.

BETA

BETA is DOUBLE PRECISION.
 On entry, BETA specifies the scalar beta. When BETA is
 supplied as zero then Y need not be set on input.

Y

Y is DOUBLE PRECISION array of dimension at least
 ( 1 + ( n - 1 )*abs( INCY ) ).
 Before entry, the incremented array Y must contain the n
 element vector y. On exit, Y is overwritten by the updated
 vector y.

INCY

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

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

Level 2 Blas routine.
The vector and matrix arguments are not referenced when N = 0, or M = 0

-- 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 148 of file dspmv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dspmv(3) is an alias of dspmv.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK