# dger (l) - Linux Manuals

## dger: performs the rank 1 operation A := alpha*x*yaq + A,

## NAME

DGER - performs the rank 1 operation A := alpha*x*yaq + A,## SYNOPSIS

- SUBROUTINE DGER(M,N,ALPHA,X,INCX,Y,INCY,A,LDA)

- DOUBLE PRECISION ALPHA

- INTEGER INCX,INCY,LDA,M,N

- DOUBLE PRECISION A(LDA,*),X(*),Y(*)

## PURPOSE

DGER performs the rank 1 operation
where alpha is a scalar, x is an m element vector, y is an n element
vector and A is an m by n matrix.

## ARGUMENTS

- M - INTEGER.
- On entry, M specifies the number of rows of the matrix A. M must be at least zero. Unchanged on exit.
- N - INTEGER.
- On entry, N specifies the number of columns of the matrix A. N must be at least zero. Unchanged on exit.
- ALPHA - DOUBLE PRECISION.
- On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
- X - DOUBLE PRECISION array of dimension at least
- ( 1 + ( m - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the m element vector x. Unchanged on exit.
- INCX - INTEGER.
- On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.
- Y - 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. Unchanged on exit.
- INCY - INTEGER.
- On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Unchanged on exit.
- A - DOUBLE PRECISION array of DIMENSION ( LDA, n ).
- Before entry, the leading m by n part of the array A must contain the matrix of coefficients. On exit, A is overwritten by the updated matrix.
- LDA - 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 ). Unchanged on exit.

## 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.