--- rpl/lapack/lapack/dlarrv.f	2017/06/17 10:53:56	1.19
+++ rpl/lapack/lapack/dlarrv.f	2023/08/07 08:38:58	1.24
@@ -68,8 +68,14 @@
 *> \verbatim
 *>          VU is DOUBLE PRECISION
 *>          Upper bound of the interval that contains the desired
-*>          eigenvalues. VL < VU. Needed to compute gaps on the left or right
-*>          end of the extremal eigenvalues in the desired RANGE.
+*>          eigenvalues. VL < VU. 
+*>          Note: VU is currently not used by this implementation of DLARRV, VU is
+*>          passed to DLARRV because it could be used compute gaps on the right end
+*>          of the extremal eigenvalues. However, with not much initial accuracy in
+*>          LAMBDA and VU, the formula can lead to an overestimation of the right gap
+*>          and thus to inadequately early RQI 'convergence'. This is currently
+*>          prevented this by forcing a small right gap. And so it turns out that VU
+*>          is currently not used by this implementation of DLARRV.
 *> \endverbatim
 *>
 *> \param[in,out] D
@@ -143,7 +149,7 @@
 *>          RTOL2 is DOUBLE PRECISION
 *>           Parameters for bisection.
 *>           An interval [LEFT,RIGHT] has converged if
-*>           RIGHT-LEFT.LT.MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) )
+*>           RIGHT-LEFT < MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) )
 *> \endverbatim
 *>
 *> \param[in,out] W
@@ -266,8 +272,6 @@
 *> \author Univ. of Colorado Denver
 *> \author NAG Ltd.
 *
-*> \date June 2016
-*
 *> \ingroup doubleOTHERauxiliary
 *
 *> \par Contributors:
@@ -286,10 +290,9 @@
      $                   IBLOCK, INDEXW, GERS, Z, LDZ, ISUPPZ,
      $                   WORK, IWORK, INFO )
 *
-*  -- 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..--
-*     June 2016
 *
 *     .. Scalar Arguments ..
       INTEGER            DOL, DOU, INFO, LDZ, M, N
@@ -344,6 +347,13 @@
 *     ..
 
       INFO = 0
+*
+*     Quick return if possible
+*
+      IF( (N.LE.0).OR.(M.LE.0) ) THEN
+         RETURN
+      END IF
+*
 *     The first N entries of WORK are reserved for the eigenvalues
       INDLD = N+1
       INDLLD= 2*N+1