--- rpl/lapack/lapack/dlapy3.f 2012/12/14 14:22:33 1.12
+++ rpl/lapack/lapack/dlapy3.f 2023/08/07 08:38:55 1.18
@@ -2,28 +2,28 @@
*
* =========== DOCUMENTATION ===========
*
-* Online html documentation available at
-* http://www.netlib.org/lapack/explore-html/
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
-*> Download DLAPY3 + dependencies
-*>
-*> [TGZ]
-*>
-*> [ZIP]
-*>
+*> Download DLAPY3 + dependencies
+*>
+*> [TGZ]
+*>
+*> [ZIP]
+*>
*> [TXT]
-*> \endhtmlonly
+*> \endhtmlonly
*
* Definition:
* ===========
*
* DOUBLE PRECISION FUNCTION DLAPY3( X, Y, Z )
-*
+*
* .. Scalar Arguments ..
* DOUBLE PRECISION X, Y, Z
* ..
-*
+*
*
*> \par Purpose:
* =============
@@ -31,7 +31,7 @@
*> \verbatim
*>
*> DLAPY3 returns sqrt(x**2+y**2+z**2), taking care not to cause
-*> unnecessary overflow.
+*> unnecessary overflow and unnecessary underflow.
*> \endverbatim
*
* Arguments:
@@ -56,22 +56,19 @@
* Authors:
* ========
*
-*> \author Univ. of Tennessee
-*> \author Univ. of California Berkeley
-*> \author Univ. of Colorado Denver
-*> \author NAG Ltd.
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
*
-*> \date September 2012
-*
-*> \ingroup auxOTHERauxiliary
+*> \ingroup OTHERauxiliary
*
* =====================================================================
DOUBLE PRECISION FUNCTION DLAPY3( X, Y, Z )
*
-* -- LAPACK auxiliary routine (version 3.4.2) --
+* -- LAPACK auxiliary routine --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-* September 2012
*
* .. Scalar Arguments ..
DOUBLE PRECISION X, Y, Z
@@ -84,18 +81,22 @@
PARAMETER ( ZERO = 0.0D0 )
* ..
* .. Local Scalars ..
- DOUBLE PRECISION W, XABS, YABS, ZABS
+ DOUBLE PRECISION W, XABS, YABS, ZABS, HUGEVAL
+* ..
+* .. External Subroutines ..
+ DOUBLE PRECISION DLAMCH
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, MAX, SQRT
* ..
* .. Executable Statements ..
*
+ HUGEVAL = DLAMCH( 'Overflow' )
XABS = ABS( X )
YABS = ABS( Y )
ZABS = ABS( Z )
W = MAX( XABS, YABS, ZABS )
- IF( W.EQ.ZERO ) THEN
+ IF( W.EQ.ZERO .OR. W.GT.HUGEVAL ) THEN
* W can be zero for max(0,nan,0)
* adding all three entries together will make sure
* NaN will not disappear.