--- rpl/lapack/lapack/dlapy3.f	2018/05/29 07:17:58	1.17
+++ rpl/lapack/lapack/dlapy3.f	2023/08/07 08:38:55	1.18
@@ -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:
@@ -61,17 +61,14 @@
 *> \author Univ. of Colorado Denver
 *> \author NAG Ltd.
 *
-*> \date December 2016
-*
 *> \ingroup OTHERauxiliary
 *
 *  =====================================================================
       DOUBLE PRECISION FUNCTION DLAPY3( X, Y, Z )
 *
-*  -- LAPACK auxiliary routine (version 3.7.0) --
+*  -- LAPACK auxiliary routine --
 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-*     December 2016
 *
 *     .. 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.