NAG C Library Function Document

nag_machine_precision (X02AJC)

Keyword Search:

NAG C Library Manual, Mark 26

NAG Library Manual, Mark 26

NAG AD Library Manual, Mark 26

x02 Chapter Contents

x02 Chapter Introduction

▸▿ 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

nag_machine_precision (X02AJC) returns

ε

, the value machine precision.

2

Specification

#include <nag.h>

#include <nagx02.h>

double

nag_machine_precision

3

Description

nag_machine_precision (X02AJC) is a constant defined in the C Header file.

nag_machine_precision (X02AJC) returns machine precision, computed as

ε = \frac{1}{2} \times b^{1 - p}

, where

b

is the arithmetic base (see nag_real_base (X02BHC)) and

p

is the number of significant base-

b

digits (see nag_real_base_digits (X02BJC)).

It is important to note that the definition of

ε

here differs from that in ISO Fortran 95 (1997).

4

References

ISO Fortran 95 (1997) ISO Fortran 95 programming language (ISO/IEC 1539–1:1997)

5

Arguments

None.

6

Error Indicators and Warnings

None.

7

Accuracy

None.

8

Parallelism and Performance

nag_machine_precision (X02AJC) is not threaded in any implementation.

9

Further Comments

None.

10

Example

None.

NAG C Library Manual, Mark 26

NAG Library Manual, Mark 26

NAG AD Library Manual, Mark 26

x02 Chapter Contents

x02 Chapter Introduction

NAG C Library Function Document

nag_machine_precision (X02AJC)

▸▿ 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