Annotation of rpl/lapack/lapack/dlapy2.f, revision 1.8
1.8 ! bertrand 1: *> \brief \b DLAPY2
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 9: *> Download DLAPY2 + dependencies
! 10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlapy2.f">
! 11: *> [TGZ]</a>
! 12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlapy2.f">
! 13: *> [ZIP]</a>
! 14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlapy2.f">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * DOUBLE PRECISION FUNCTION DLAPY2( X, Y )
! 22: *
! 23: * .. Scalar Arguments ..
! 24: * DOUBLE PRECISION X, Y
! 25: * ..
! 26: *
! 27: *
! 28: *> \par Purpose:
! 29: * =============
! 30: *>
! 31: *> \verbatim
! 32: *>
! 33: *> DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary
! 34: *> overflow.
! 35: *> \endverbatim
! 36: *
! 37: * Arguments:
! 38: * ==========
! 39: *
! 40: *> \param[in] X
! 41: *> \verbatim
! 42: *> X is DOUBLE PRECISION
! 43: *> \endverbatim
! 44: *>
! 45: *> \param[in] Y
! 46: *> \verbatim
! 47: *> Y is DOUBLE PRECISION
! 48: *> X and Y specify the values x and y.
! 49: *> \endverbatim
! 50: *
! 51: * Authors:
! 52: * ========
! 53: *
! 54: *> \author Univ. of Tennessee
! 55: *> \author Univ. of California Berkeley
! 56: *> \author Univ. of Colorado Denver
! 57: *> \author NAG Ltd.
! 58: *
! 59: *> \date November 2011
! 60: *
! 61: *> \ingroup auxOTHERauxiliary
! 62: *
! 63: * =====================================================================
1.1 bertrand 64: DOUBLE PRECISION FUNCTION DLAPY2( X, Y )
65: *
1.8 ! bertrand 66: * -- LAPACK auxiliary routine (version 3.4.0) --
1.1 bertrand 67: * -- LAPACK is a software package provided by Univ. of Tennessee, --
68: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.8 ! bertrand 69: * November 2011
1.1 bertrand 70: *
71: * .. Scalar Arguments ..
72: DOUBLE PRECISION X, Y
73: * ..
74: *
75: * =====================================================================
76: *
77: * .. Parameters ..
78: DOUBLE PRECISION ZERO
79: PARAMETER ( ZERO = 0.0D0 )
80: DOUBLE PRECISION ONE
81: PARAMETER ( ONE = 1.0D0 )
82: * ..
83: * .. Local Scalars ..
84: DOUBLE PRECISION W, XABS, YABS, Z
85: * ..
86: * .. Intrinsic Functions ..
87: INTRINSIC ABS, MAX, MIN, SQRT
88: * ..
89: * .. Executable Statements ..
90: *
91: XABS = ABS( X )
92: YABS = ABS( Y )
93: W = MAX( XABS, YABS )
94: Z = MIN( XABS, YABS )
95: IF( Z.EQ.ZERO ) THEN
96: DLAPY2 = W
97: ELSE
98: DLAPY2 = W*SQRT( ONE+( Z / W )**2 )
99: END IF
100: RETURN
101: *
102: * End of DLAPY2
103: *
104: END
CVSweb interface <joel.bertrand@systella.fr>