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+*> \brief \b DLAPY3
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+*> \htmlonly
+*> Download DLAPY3 + dependencies
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlapy3.f">
+*> [TGZ]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlapy3.f">
+*> [ZIP]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlapy3.f">
+*> [TXT]</a>
+*> \endhtmlonly
+*
+* Definition:
+* ===========
+*
+* DOUBLE PRECISION FUNCTION DLAPY3( X, Y, Z )
+*
+* .. Scalar Arguments ..
+* DOUBLE PRECISION X, Y, Z
+* ..
+*
+*
+*> \par Purpose:
+* =============
+*>
+*> \verbatim
+*>
+*> DLAPY3 returns sqrt(x**2+y**2+z**2), taking care not to cause
+*> unnecessary overflow.
+*> \endverbatim
+*
+* Arguments:
+* ==========
+*
+*> \param[in] X
+*> \verbatim
+*> X is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] Y
+*> \verbatim
+*> Y is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] Z
+*> \verbatim
+*> Z is DOUBLE PRECISION
+*> 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
+*
+* =====================================================================
+ DOUBLE PRECISION FUNCTION DLAPY3( 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 ..
+ DOUBLE PRECISION X, Y, Z
+* ..
+*
+* =====================================================================
+*
+* .. Parameters ..
+ DOUBLE PRECISION ZERO
+ PARAMETER ( ZERO = 0.0D0 )
+* ..
+* .. Local Scalars ..
+ DOUBLE PRECISION 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.
+ DLAPY3 = XABS + YABS + ZABS
+ ELSE
+ DLAPY3 = W*SQRT( ( XABS / W )**2+( YABS / W )**2+
+ $ ( ZABS / W )**2 )
+ END IF
+ RETURN
+*
+* End of DLAPY3
+*
+ END