--- rpl/lapack/lapack/dlapy2.f 2010/01/26 15:22:45 1.1
+++ rpl/lapack/lapack/dlapy2.f 2023/08/07 08:38:55 1.19
@@ -1,27 +1,74 @@
+*> \brief \b DLAPY2 returns sqrt(x2+y2).
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+*> \htmlonly
+*> Download DLAPY2 + dependencies
+*>
+*> [TGZ]
+*>
+*> [ZIP]
+*>
+*> [TXT]
+*> \endhtmlonly
+*
+* Definition:
+* ===========
+*
+* DOUBLE PRECISION FUNCTION DLAPY2( X, Y )
+*
+* .. Scalar Arguments ..
+* DOUBLE PRECISION X, Y
+* ..
+*
+*
+*> \par Purpose:
+* =============
+*>
+*> \verbatim
+*>
+*> DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary
+*> overflow and unnecessary underflow.
+*> \endverbatim
+*
+* Arguments:
+* ==========
+*
+*> \param[in] X
+*> \verbatim
+*> X is DOUBLE PRECISION
+*> \endverbatim
+*>
+*> \param[in] Y
+*> \verbatim
+*> Y is DOUBLE PRECISION
+*> X and Y specify the values x and y.
+*> \endverbatim
+*
+* Authors:
+* ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \ingroup OTHERauxiliary
+*
+* =====================================================================
DOUBLE PRECISION FUNCTION DLAPY2( X, Y )
*
-* -- LAPACK auxiliary routine (version 3.2) --
+* -- LAPACK auxiliary routine --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-* November 2006
*
* .. Scalar Arguments ..
DOUBLE PRECISION X, Y
* ..
*
-* Purpose
-* =======
-*
-* DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary
-* overflow.
-*
-* Arguments
-* =========
-*
-* X (input) DOUBLE PRECISION
-* Y (input) DOUBLE PRECISION
-* X and Y specify the values x and y.
-*
* =====================================================================
*
* .. Parameters ..
@@ -31,21 +78,37 @@
PARAMETER ( ONE = 1.0D0 )
* ..
* .. Local Scalars ..
- DOUBLE PRECISION W, XABS, YABS, Z
+ DOUBLE PRECISION W, XABS, YABS, Z, HUGEVAL
+ LOGICAL X_IS_NAN, Y_IS_NAN
+* ..
+* .. External Functions ..
+ LOGICAL DISNAN
+ EXTERNAL DISNAN
+* ..
+* .. External Subroutines ..
+ DOUBLE PRECISION DLAMCH
* ..
* .. 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 )
+ X_IS_NAN = DISNAN( X )
+ Y_IS_NAN = DISNAN( Y )
+ IF ( X_IS_NAN ) DLAPY2 = X
+ IF ( Y_IS_NAN ) DLAPY2 = Y
+ HUGEVAL = DLAMCH( 'Overflow' )
+*
+ IF ( .NOT.( X_IS_NAN.OR.Y_IS_NAN ) ) THEN
+ XABS = ABS( X )
+ YABS = ABS( Y )
+ W = MAX( XABS, YABS )
+ Z = MIN( XABS, YABS )
+ IF( Z.EQ.ZERO .OR. W.GT.HUGEVAL ) THEN
+ DLAPY2 = W
+ ELSE
+ DLAPY2 = W*SQRT( ONE+( Z / W )**2 )
+ END IF
END IF
RETURN
*