DLAISNAN(1) | LAPACK auxiliary routine (version 3.2) | DLAISNAN(1) |
NAME¶
DLAISNAN - routine i not for general use
SYNOPSIS¶
- LOGICAL FUNCTION
- DLAISNAN(DIN1,DIN2)
DOUBLE PRECISION DIN1,DIN2
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.
ARGUMENTS¶
- DIN1 (input) DOUBLE PRECISION
- DIN2 (input) DOUBLE PRECISION Two numbers to compare for inequality.
November 2008 | LAPACK auxiliary routine (version 3.2) |