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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