NAG FL Interface
x02ahf (sinarg_​max)

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FL Specification Language:

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

Fortran Interface
Function x02ahf ( x)
Real (Kind=nag_wp) :: x02ahf
Real (Kind=nag_wp), Intent (In) :: x
C Header Interface
#include <nag.h>
double  x02ahf_ (double *x)
The routine may be called by the names x02ahf or nagf_machine_sinarg_max.

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


5 Arguments

1: x Real (Kind=nag_wp) Dummy

6 Error Indicators and Warnings


7 Accuracy

Not applicable.

8 Parallelism and Performance

Background information to multithreading can be found in the Multithreading documentation.
x02ahf is not threaded in any implementation.

9 Further Comments


10 Example

See x02ajf.