double precision function dlapy2	(	double precision	X,
		double precision	Y
	)

DLAPY2 returns sqrt(x2+y2).

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Purpose:

 DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary
 overflow.

Parameters

[in]	X	X is DOUBLE PRECISION
[in]	Y	Y is DOUBLE PRECISION X and Y specify the values x and y.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date

September 2012

Definition at line 65 of file dlapy2.f.

*
*  -- LAPACK auxiliary routine (version 3.4.2) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     September 2012
*
*     .. Scalar Arguments ..
      DOUBLE PRECISION   x, y
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      DOUBLE PRECISION   zero
      parameter                ( zero = 0.0d0 )
      DOUBLE PRECISION   one
      parameter                ( one = 1.0d0 )
*     ..
*     .. Local Scalars ..
      DOUBLE PRECISION   w, xabs, yabs, z
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          abs, max, min, sqrt
*     ..
*     .. Executable Statements ..
*
      xabs = abs( x )
      yabs = abs( y )
      w = max( xabs, yabs )
      z = min( xabs, yabs )
      IF( z.EQ.zero ) THEN
         dlapy2 = w
      ELSE
         dlapy2 = w*sqrt( one+( z / w )**2 )
      END IF
      RETURN
*
*     End of DLAPY2
*