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  4. dlaisnan(3)

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dlaisnan.f(3) LAPACK dlaisnan.f(3)

NAME

dlaisnan.f

SYNOPSIS

Functions/Subroutines


logical function dlaisnan (DIN1, DIN2)
DLAISNAN tests input for NaN by comparing two arguments for inequality.

Function/Subroutine Documentation

logical function dlaisnan (double precision, intent(in) DIN1, double precision, intent(in) DIN2)

DLAISNAN tests input for NaN by comparing two arguments for inequality.

Purpose: 



 This routine is not for general use.  It exists solely to avoid


 over-optimization in DISNAN.


 DLAISNAN checks for NaNs by comparing its two arguments for


 inequality.  NaN is the only floating-point value where NaN != NaN


 returns .TRUE.  To check for NaNs, pass the same variable as both


 arguments.


 A compiler must assume that the two arguments are


 not the same variable, and the test will not be optimized away.


 Interprocedural or whole-program optimization may delete this


 test.  The ISNAN functions will be replaced by the correct


 Fortran 03 intrinsic once the intrinsic is widely available.

Parameters:

DIN1 



          DIN1 is DOUBLE PRECISION

DIN2



          DIN2 is DOUBLE PRECISION


          Two numbers to compare for inequality.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

June 2017

Definition at line 76 of file dlaisnan.f.

Author

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Tue Nov 14 2017 Version 3.8.0