BLAS/SRC/sgemv.f(3)

NAME
BLAS/SRC/sgemv.f

SYNOPSIS

  Functions/Subroutines
subroutine sgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy)
SGEMV

Function/Subroutine Documentation

  subroutine sgemv (character trans, integer m, integer n, real alpha, real, dimension(lda,*) a, integer lda, real, dimension(*) x, integer incx, real beta, real, dimension(*) y, integer incy)

SGEMV

Purpose:

     SGEMV  performs one of the matrix-vector operations
        y := alpha*A*x + beta*y,   or   y := alpha*A**T*x + beta*y,
     where alpha and beta are scalars, x and y are vectors and A is an
     m by n matrix.

Parameters
    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   y := alpha*A*x + beta*y.
                  TRANS = 'T' or 't'   y := alpha*A**T*x + beta*y.
                  TRANS = 'C' or 'c'   y := alpha*A**T*x + beta*y.

    M

              M is INTEGER
               On entry, M specifies the number of rows of the matrix A.
               M must be at least zero.

    N

              N is INTEGER
               On entry, N specifies the number of columns 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, dimension ( LDA, N )
               Before entry, the leading m by n part of the array A must
               contain the matrix of coefficients.

    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, m ).

    X

              X is REAL array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'
               and at least
               ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.
               Before entry, the incremented array X must contain the
               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, dimension at least
               ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'
               and at least
               ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.
               Before entry with BETA non-zero, the incremented array Y
               must contain the vector y. On exit, Y is overwritten by the
               updated vector y.
               If either m or n is zero, then Y not referenced and the function
               performs a quick return.

    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.

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 157 of file sgemv.f.

Author

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