ssymv.f(3)

NAME
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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