NAG FL Interface
f06bmf (dnorm)

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FL Specification Language:


1 Purpose

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

2 Specification

Fortran Interface
Function f06bmf ( scal, ssq)
Real (Kind=nag_wp) :: f06bmf
Real (Kind=nag_wp), Intent (In) :: scal, ssq
C Header Interface
#include <nag.h>
double  f06bmf_ (const double *scal, const double *ssq)
The routine may be called by the names f06bmf or nagf_blas_dnorm.

3 Description

f06bmf completes the safe computation of the Euclidean length of a vector, following a call to f06fjf or f06kjf which return values α and ξ such that
x22=α2ξ.  
f06bmf returns, via the function name, the value
min(αξ,flmax),  
where flmax is the value given by 1/(x02amf).

4 References

None.

5 Arguments

1: scal Real (Kind=nag_wp) Input
On entry: the scaling factor α, returned by f06fjf or f06kjf.
Constraint: scal0.0.
2: ssq Real (Kind=nag_wp) Input
On entry: the scaled sum of squares ξ, returned by f06fjf or f06kjf.
Constraint: ssq1.0.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

f06bmf is not threaded in any implementation.

9 Further Comments

None.

10 Example

None.