# zgeru

```ZGERU(1)                         BLAS routine                         ZGERU(1)

NAME
ZGERU - performs the rank 1 operation   A := alpha*x*y' + A,

SYNOPSIS
SUBROUTINE ZGERU(M,N,ALPHA,X,INCX,Y,INCY,A,LDA)

DOUBLE                                      COMPLEX ALPHA

INTEGER                                     INCX,INCY,LDA,M,N

DOUBLE                                      COMPLEX
A(LDA,*),X(*),Y(*)

PURPOSE
ZGERU  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  - COMPLEX*16      .
On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.

X      - COMPLEX*16       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      - COMPLEX*16       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      - COMPLEX*16       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.

BLAS routine                     November 2008                        ZGERU(1)```