ssymv.f man page

ssymv.f —

Synopsis

Functions/Subroutines

subroutine ssymv (UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY)
SSYMV

Function/Subroutine Documentation

subroutine ssymv (characterUPLO, integerN, realALPHA, real, dimension(lda,*)A, integerLDA, real, dimension(*)X, integerINCX, realBETA, real, dimension(*)Y, integerINCY)

SSYMV Purpose:

SSYMV  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.

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 REAL
 On entry, ALPHA specifies the scalar alpha.

A

A is REAL array of 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.
 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.

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 ).

X

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

Y

Y is REAL 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 153 of file ssymv.f.

Author

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Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK