naginterfaces.library.blas.dger

naginterfaces.library.blas.dger(alpha, x, y, a)

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

For full information please refer to the NAG Library document for f06pm

https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f06/f06pmf.html

Parameters

alphafloat

The scalar $\alpha$.

xfloat, array-like, shape $\left(m\right)$

The $m$ element vector $x$.

yfloat, array-like, shape $\left(n\right)$

The $n$-element vector $y$.

afloat, array-like, shape $(m,n)$

The $m\times n$ matrix $A$.

Returns

afloat, ndarray, shape $(m,n)$

The updated matrix $A$.

Raises

NagValueError

(errno $1$)

On entry, error in parameter $\text{m}$.

Constraint: $m\ge 0$.

(errno $2$)

On entry, error in parameter $\text{n}$.

Constraint: $n\ge 0$.

(errno $5$)

On entry, error in parameter $\text{incx}$.

Constraint: $\text{incx}\ne 0$.

(errno $7$)

On entry, error in parameter $\text{incy}$.

Constraint: $\text{incy}\ne 0$.

Notes

In the NAG Library the traditional C interface for this routine uses a different algorithmic base. Please contact NAG if you have any questions about compatibility.

dger performs the rank-1 update operation

$$A\leftarrow \alpha x{y}^T+A\text{,}$$

where $A$ is an $m\times n$ real matrix, $x$ is an $m$ element real vector, $y$ is an $n$-element real vector, and $\alpha$ is a real scalar.