forked from lijiext/lammps
204 lines
4.5 KiB
Fortran
204 lines
4.5 KiB
Fortran
*> \brief \b IEEECK
|
|
*
|
|
* =========== DOCUMENTATION ===========
|
|
*
|
|
* Online html documentation available at
|
|
* http://www.netlib.org/lapack/explore-html/
|
|
*
|
|
*> \htmlonly
|
|
*> Download IEEECK + dependencies
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ieeeck.f">
|
|
*> [TGZ]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ieeeck.f">
|
|
*> [ZIP]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ieeeck.f">
|
|
*> [TXT]</a>
|
|
*> \endhtmlonly
|
|
*
|
|
* Definition:
|
|
* ===========
|
|
*
|
|
* INTEGER FUNCTION IEEECK( ISPEC, ZERO, ONE )
|
|
*
|
|
* .. Scalar Arguments ..
|
|
* INTEGER ISPEC
|
|
* REAL ONE, ZERO
|
|
* ..
|
|
*
|
|
*
|
|
*> \par Purpose:
|
|
* =============
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> IEEECK is called from the ILAENV to verify that Infinity and
|
|
*> possibly NaN arithmetic is safe (i.e. will not trap).
|
|
*> \endverbatim
|
|
*
|
|
* Arguments:
|
|
* ==========
|
|
*
|
|
*> \param[in] ISPEC
|
|
*> \verbatim
|
|
*> ISPEC is INTEGER
|
|
*> Specifies whether to test just for inifinity arithmetic
|
|
*> or whether to test for infinity and NaN arithmetic.
|
|
*> = 0: Verify infinity arithmetic only.
|
|
*> = 1: Verify infinity and NaN arithmetic.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] ZERO
|
|
*> \verbatim
|
|
*> ZERO is REAL
|
|
*> Must contain the value 0.0
|
|
*> This is passed to prevent the compiler from optimizing
|
|
*> away this code.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] ONE
|
|
*> \verbatim
|
|
*> ONE is REAL
|
|
*> Must contain the value 1.0
|
|
*> This is passed to prevent the compiler from optimizing
|
|
*> away this code.
|
|
*>
|
|
*> RETURN VALUE: INTEGER
|
|
*> = 0: Arithmetic failed to produce the correct answers
|
|
*> = 1: Arithmetic produced the correct answers
|
|
*> \endverbatim
|
|
*
|
|
* Authors:
|
|
* ========
|
|
*
|
|
*> \author Univ. of Tennessee
|
|
*> \author Univ. of California Berkeley
|
|
*> \author Univ. of Colorado Denver
|
|
*> \author NAG Ltd.
|
|
*
|
|
*> \date November 2011
|
|
*
|
|
*> \ingroup auxOTHERauxiliary
|
|
*
|
|
* =====================================================================
|
|
INTEGER FUNCTION IEEECK( ISPEC, ZERO, ONE )
|
|
*
|
|
* -- LAPACK auxiliary routine (version 3.4.0) --
|
|
* -- LAPACK is a software package provided by Univ. of Tennessee, --
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
|
* November 2011
|
|
*
|
|
* .. Scalar Arguments ..
|
|
INTEGER ISPEC
|
|
REAL ONE, ZERO
|
|
* ..
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Local Scalars ..
|
|
REAL NAN1, NAN2, NAN3, NAN4, NAN5, NAN6, NEGINF,
|
|
$ NEGZRO, NEWZRO, POSINF
|
|
* ..
|
|
* .. Executable Statements ..
|
|
IEEECK = 1
|
|
*
|
|
POSINF = ONE / ZERO
|
|
IF( POSINF.LE.ONE ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
NEGINF = -ONE / ZERO
|
|
IF( NEGINF.GE.ZERO ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
NEGZRO = ONE / ( NEGINF+ONE )
|
|
IF( NEGZRO.NE.ZERO ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
NEGINF = ONE / NEGZRO
|
|
IF( NEGINF.GE.ZERO ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
NEWZRO = NEGZRO + ZERO
|
|
IF( NEWZRO.NE.ZERO ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
POSINF = ONE / NEWZRO
|
|
IF( POSINF.LE.ONE ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
NEGINF = NEGINF*POSINF
|
|
IF( NEGINF.GE.ZERO ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
POSINF = POSINF*POSINF
|
|
IF( POSINF.LE.ONE ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
*
|
|
*
|
|
*
|
|
* Return if we were only asked to check infinity arithmetic
|
|
*
|
|
IF( ISPEC.EQ.0 )
|
|
$ RETURN
|
|
*
|
|
NAN1 = POSINF + NEGINF
|
|
*
|
|
NAN2 = POSINF / NEGINF
|
|
*
|
|
NAN3 = POSINF / POSINF
|
|
*
|
|
NAN4 = POSINF*ZERO
|
|
*
|
|
NAN5 = NEGINF*NEGZRO
|
|
*
|
|
NAN6 = NAN5*ZERO
|
|
*
|
|
IF( NAN1.EQ.NAN1 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
IF( NAN2.EQ.NAN2 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
IF( NAN3.EQ.NAN3 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
IF( NAN4.EQ.NAN4 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
IF( NAN5.EQ.NAN5 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
IF( NAN6.EQ.NAN6 ) THEN
|
|
IEEECK = 0
|
|
RETURN
|
|
END IF
|
|
*
|
|
RETURN
|
|
END
|