NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X02 (Machine) Chapter Contents
X02 (Machine) Chapter Introduction
x02aj:  FL   CL   CPP   AD 

NAG FL Interface
x02ajf (precision)

NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X02 (Machine) Chapter Contents
X02 (Machine) Chapter Introduction
x02aj:  FL   CL   CPP   AD 

▸▿ Contents

© The Numerical Algorithms Group Ltd. 2019

1 Purpose

x02ajf returns ε, the value machine precision.

2 Specification

Fortran Interface
Function x02ajf ( )
Real (Kind=nag_wp) :: x02ajf
C Header Interface
#include <nag.h>
double  x02ajf_ ()
The routine may be called by the names x02ajf or nagf_machine_precision.

3 Description

x02ajf returns machine precision, computed as ε = 12 × b1-p , where b is the arithmetic base (see x02bhf) and p is the number of significant base-b digits (see x02bjf).
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

Not applicable.

8 Parallelism and Performance

x02ajf is not threaded in any implementation.

9 Further Comments

None.

10 Example

This example prints the values of all the functions in Chapter X02. The results will vary from one implementation of the Library to another.

10.1 Program Text

Program Text (x02ajfe.f90)

10.2 Program Data

None.

10.3 Program Results

Program Results (x02ajfe.r)
NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X02 (Machine) Chapter Contents
X02 (Machine) Chapter Introduction
x02aj:  FL   CL   CPP   AD 
© The Numerical Algorithms Group Ltd. 2019