X02AJF (PDF version)
X02 Chapter Contents
X02 Chapter Introduction
NAG Library Manual

NAG Library Routine Document

X02AJF

Note:  before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.

+− Contents

    1  Purpose
    2  Specification
    3  Description
    4  References
    5  Parameters
    6  Error Indicators and Warnings
    7  Accuracy
    8  Further Comments
+− 9  Example

1  Purpose

X02AJF returns ε, the value machine precision.

2  Specification

FUNCTION X02AJF ( )
REAL (KIND=nag_wp) X02AJF

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 (1997).

4  References

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

5  Parameters

None.

6  Error Indicators and Warnings

None.

7  Accuracy

None.

8  Further Comments

None.

9  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.

9.1  Program Text

Program Text (x02ajfe.f90)

9.2  Program Data

None.

9.3  Program Results

Program Results (x02ajfe.r)

X02AJF (PDF version)
X02 Chapter Contents
X02 Chapter Introduction
NAG Library Manual
© The Numerical Algorithms Group Ltd, Oxford, UK. 2012