X02AHF (PDF version)
X02 Chapter Contents
X02 Chapter Introduction
NAG Library Manual

NAG Library Routine Document

X02AHF

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
    7  Accuracy
    9  Example

1  Purpose

X02AHF returns the largest positive argument for which the Fortran intrinsic functions SIN and COS return a result with some meaningful accuracy.

2  Specification

FUNCTION X02AHF ( X)
REAL (KIND=nag_wp) X02AHF
REAL (KIND=nag_wp)  X

3  Description

The trigonometric functions sin and cos supplied in some compiler run-time libraries do not return accurate results when their argument is large. Often the related accuracy of a result gets progressively worse as the argument gets larger. X02AHF gives a value beyond which the compiler run-time library returns results with no relative accuracy at all. Note that some run-time libraries do return accurate results for all arguments to sin and cos.

4  References

None.

5  Parameters

1:     X – REAL (KIND=nag_wp)Dummy

6  Error Indicators and Warnings

None.

7  Accuracy

None.

8  Further Comments

None.

9  Example

See Section 9 in X02AJF.

X02AHF (PDF version)
X02 Chapter Contents
X02 Chapter Introduction
NAG Library Manual

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