Page MenuHomec4science
Files F101549487

slapy3.f
No OneTemporary
Actions

File Metadata

Created
Tue, Feb 11, 12:16

slapy3.f
View Options

*> \brief \b SLAPY3
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLAPY3 + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slapy3.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slapy3.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slapy3.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* REAL FUNCTION SLAPY3( X, Y, Z )
*
* .. Scalar Arguments ..
* REAL X, Y, Z
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLAPY3 returns sqrt(x**2+y**2+z**2), taking care not to cause
*> unnecessary overflow.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] X
*> \verbatim
*> X is REAL
*> \endverbatim
*>
*> \param[in] Y
*> \verbatim
*> Y is REAL
*> \endverbatim
*>
*> \param[in] Z
*> \verbatim
*> Z is REAL
*> X, Y and Z specify the values x, y and z.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup auxOTHERauxiliary
*
* =====================================================================
REAL FUNCTION SLAPY3( X, Y, Z )
*
* -- 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 ..
REAL X, Y, Z
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ZERO
PARAMETER ( ZERO = 0.0E0 )
* ..
* .. Local Scalars ..
REAL W, XABS, YABS, ZABS
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, MAX, SQRT
* ..
* .. Executable Statements ..
*
XABS = ABS( X )
YABS = ABS( Y )
ZABS = ABS( Z )
W = MAX( XABS, YABS, ZABS )
IF( W.EQ.ZERO ) THEN
* W can be zero for max(0,nan,0)
* adding all three entries together will make sure
* NaN will not disappear.
SLAPY3 = XABS + YABS + ZABS
ELSE
SLAPY3 = W*SQRT( ( XABS / W )**2+( YABS / W )**2+
$ ( ZABS / W )**2 )
END IF
RETURN
*
* End of SLAPY3
*
END

Event Timeline

c4science · Help