NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X07 (Ieee) Chapter Contents
X07 (Ieee) Chapter Introduction
x07aa:  FL   CL   CPP   AD 

NAG FL Interface
x07aaf (is_​finite)

NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X07 (Ieee) Chapter Contents
X07 (Ieee) Chapter Introduction
x07aa:  FL   CL   CPP   AD 

▸▿ Contents

© The Numerical Algorithms Group Ltd. 2019

1 Purpose

x07aaf determines whether a floating-point number is finite.

2 Specification

Fortran Interface
Function x07aaf ( x)
Logical :: x07aaf
Real (Kind=nag_wp), Intent (In) :: x
C Header Interface
#include <nag.h>
Nag_Boolean  x07aaf_ (const double *x)
The routine may be called by the names x07aaf or nagf_ieee_is_finite.

3 Description

x07aaf returns .TRUE. if and only if x is finite, and returns .FALSE. otherwise.

4 References

IEEE (2008) Standard for Floating-Point Arithmetic IEEE Standard 754-2008 IEEE, New York.

5 Arguments

1: x – Real (Kind=nag_wp) Input
On entry: the number whose status is to be determined.

6 Error Indicators and Warnings

None.

7 Accuracy

Not applicable.

8 Parallelism and Performance

x07aaf is not threaded in any implementation.

9 Further Comments

This routine will return .FALSE. if the argument x is either infinite or a NaN (Not A Number).

10 Example

This program creates various infinities, NaNs and normal numbers and distinguishes between them.

10.1 Program Text

Program Text (x07aafe.f90)

10.2 Program Data

None.

10.3 Program Results

Program Results (x07aafe.r)
NAG Library Manual, Mark 27
Interfaces:  FL   CL   CPP   AD 
NAG FL Interface Introduction
X07 (Ieee) Chapter Contents
X07 (Ieee) Chapter Introduction
x07aa:  FL   CL   CPP   AD 
© The Numerical Algorithms Group Ltd. 2019