This manual relates to an old release of the Library.
The documentation for the current release is also available on this site.

NAG FL Interface
f06pmf (dger)

Settings help

FL Name Style:


FL Specification Language:


1 Purpose

f06pmf computes the rank-1 update of a real general matrix.

2 Specification

Fortran Interface
Subroutine f06pmf ( m, n, alpha, x, incx, y, incy, a, lda)
Integer, Intent (In) :: m, n, incx, incy, lda
Real (Kind=nag_wp), Intent (In) :: alpha, x(*), y(*)
Real (Kind=nag_wp), Intent (Inout) :: a(lda,*)
C Header Interface
#include <nag.h>
void  f06pmf_ (const Integer *m, const Integer *n, const double *alpha, const double x[], const Integer *incx, const double y[], const Integer *incy, double a[], const Integer *lda)
The routine may be called by the names f06pmf, nagf_blas_dger or its BLAS name dger.

3 Description

f06pmf performs the rank-1 update operation
AαxyT + A ,  
where A is an m×n real matrix, x is an m element real vector, y is an n-element real vector, and α is a real scalar.

4 References

None.

5 Arguments

1: m Integer Input
On entry: m, the number of rows of the matrix A.
Constraint: m0.
2: n Integer Input
On entry: n, the number of columns of the matrix A.
Constraint: n0.
3: alpha Real (Kind=nag_wp) Input
On entry: the scalar α.
4: x(*) Real (Kind=nag_wp) array Input
Note: the dimension of the array x must be at least max(1, 1+(m-1) ×|incx| ) .
On entry: the m element vector x.
If incx>0, xi must be stored in x(1+(i-1)×incx), for i=1,2,,m.
If incx<0, xi must be stored in x(1-(m-i)×incx), for i=1,2,,m.
Intermediate elements of x are not referenced.
5: incx Integer Input
On entry: the increment in the subscripts of x between successive elements of x.
Constraint: incx0.
6: y(*) Real (Kind=nag_wp) array Input
Note: the dimension of the array y must be at least max(1, 1+(n-1) ×|incy| ) .
On entry: the n-element vector y.
If incy>0, yi must be stored in y(1+(i-1)×incy), for i=1,2,,n.
If incy<0, yi must be stored in y(1-(n-i)×incy), for i=1,2,,n.
Intermediate elements of y are not referenced.
7: incy Integer Input
On entry: the increment in the subscripts of y between successive elements of y.
Constraint: incy0.
8: a(lda,*) Real (Kind=nag_wp) array Input/Output
Note: the second dimension of the array a must be at least n.
On entry: the m×n matrix A.
On exit: the updated matrix A.
9: lda Integer Input
On entry: the first dimension of the array a as declared in the (sub)program from which f06pmf is called.
Constraint: lda max(1,m) .

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

f06pmf is not threaded in any implementation.

9 Further Comments

None.

10 Example

None.