NAG Library Routine Document

1Purpose

f06bmf completes the safe computation of the Euclidean length of a vector, following a call to f06fjf or f06kjf.

2Specification

Fortran Interface
 Function f06bmf ( scal, ssq)
 Real (Kind=nag_wp) :: f06bmf Real (Kind=nag_wp), Intent (In) :: scal, ssq
#include nagmk26.h
 double f06bmf_ (const double *scal, const double *ssq)

3Description

f06bmf completes the safe computation of the Euclidean length of a vector, following a call to f06fjf or f06kjf which return values $\alpha$ and $\xi$ such that
 $x22=α2ξ.$
f06bmf returns, via the function name, the value
 $minα⁢ξ,flmax,$
where $\mathit{flmax}$ is the value given by $1/\left({\mathbf{x02amf}}\right)$.

None.

5Arguments

1:     $\mathbf{scal}$ – Real (Kind=nag_wp)Input
On entry: the scaling factor $\alpha$, returned by f06fjf or f06kjf.
Constraint: ${\mathbf{scal}}\ge 0.0$.
2:     $\mathbf{ssq}$ – Real (Kind=nag_wp)Input
On entry: the scaled sum of squares $\xi$, returned by f06fjf or f06kjf.
Constraint: ${\mathbf{ssq}}\ge 1.0$.

None.

Not applicable.

8Parallelism and Performance

f06bmf is not threaded in any implementation.