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NAG Library Routine Document

f06bmf (dnorm)

▸▿ Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

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 nagmk26.h

double

f06bmf_ ( const double *scal, const double *ssq)

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

{‖x‖}_{2}^{2} = α^{2} ξ .

f06bmf returns, via the function name, the value

\min (α \sqrt{ξ}, 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: $scal \geq 0.0$ .
2: $ssq$ – Real (Kind=nag_wp)Input: On entry: the scaled sum of squares $ξ$ , returned by f06fjf or f06kjf.

Constraint: $ssq \geq 1.0$ .

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.

f06bmf (PDF version)

F06 (blas) Chapter Contents

F06 (blas) Chapter Introduction

NAG Library Manual

NAG Library Routine Document

f06bmf (dnorm)

▸▿ Contents

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

6 Error Indicators and Warnings

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

6

Error Indicators and Warnings

7

Accuracy

8

Parallelism and Performance

9

Further Comments

10

Example