nag_machine_precision (X02AJC) (PDF version)
x02 Chapter Contents
x02 Chapter Introduction
NAG C Library Manual

NAG Library Function Document

nag_machine_precision (X02AJC)

+ Contents

    1  Purpose
    7  Accuracy
    9  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 = 12 × b1-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 (1997).

4  References

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

5  Arguments

None.

6  Error Indicators and Warnings

None.

7  Accuracy

None.

8  Further Comments

None.

9  Example

None.

nag_machine_precision (X02AJC) (PDF version)
x02 Chapter Contents
x02 Chapter Introduction
NAG C Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2012