--- rpl/lapack/blas/drotmg.f	2012/12/14 14:22:02	1.11
+++ rpl/lapack/blas/drotmg.f	2023/08/07 08:38:43	1.17
@@ -2,21 +2,21 @@
 *
 *  =========== 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/
 *
 *  Definition:
 *  ===========
 *
 *       SUBROUTINE DROTMG(DD1,DD2,DX1,DY1,DPARAM)
-* 
+*
 *       .. Scalar Arguments ..
 *       DOUBLE PRECISION DD1,DD2,DX1,DY1
 *       ..
 *       .. Array Arguments ..
 *       DOUBLE PRECISION DPARAM(5)
 *       ..
-*  
+*
 *
 *> \par Purpose:
 *  =============
@@ -65,9 +65,9 @@
 *>          DY1 is DOUBLE PRECISION
 *> \endverbatim
 *>
-*> \param[in,out] DPARAM
+*> \param[out] DPARAM
 *> \verbatim
-*>          DPARAM is DOUBLE PRECISION array, dimension 5
+*>          DPARAM is DOUBLE PRECISION array, dimension (5)
 *>     DPARAM(1)=DFLAG
 *>     DPARAM(2)=DH11
 *>     DPARAM(3)=DH21
@@ -78,22 +78,19 @@
 *  Authors:
 *  ========
 *
-*> \author Univ. of Tennessee 
-*> \author Univ. of California Berkeley 
-*> \author Univ. of Colorado Denver 
-*> \author NAG Ltd. 
-*
-*> \date November 2011
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
 *
 *> \ingroup double_blas_level1
 *
 *  =====================================================================
       SUBROUTINE DROTMG(DD1,DD2,DX1,DY1,DPARAM)
 *
-*  -- Reference BLAS level1 routine (version 3.4.0) --
+*  -- Reference BLAS level1 routine --
 *  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-*     November 2011
 *
 *     .. Scalar Arguments ..
       DOUBLE PRECISION DD1,DD2,DX1,DY1
@@ -135,7 +132,7 @@
             DFLAG = -TWO
             DPARAM(1) = DFLAG
             RETURN
-         END IF 
+         END IF
 *        REGULAR-CASE..
          DP1 = DD1*DX1
          DQ2 = DP2*DY1
@@ -152,6 +149,19 @@
              DD1 = DD1/DU
              DD2 = DD2/DU
              DX1 = DX1*DU
+           ELSE
+*            This code path if here for safety. We do not expect this
+*            condition to ever hold except in edge cases with rounding
+*            errors. See DOI: 10.1145/355841.355847
+             DFLAG = -ONE
+             DH11 = ZERO
+             DH12 = ZERO
+             DH21 = ZERO
+             DH22 = ZERO
+*
+             DD1 = ZERO
+             DD2 = ZERO
+             DX1 = ZERO
            END IF
          ELSE
 
@@ -203,7 +213,7 @@
                END IF
             ENDDO
          END IF
-  
+
          IF (DD2.NE.ZERO) THEN
             DO WHILE ( (DABS(DD2).LE.RGAMSQ) .OR. (DABS(DD2).GE.GAMSQ) )
                IF (DFLAG.EQ.ZERO) THEN
@@ -223,10 +233,10 @@
                   DD2 = DD2/GAM**2
                   DH21 = DH21*GAM
                   DH22 = DH22*GAM
-               END IF      
+               END IF
             END DO
          END IF
-     
+
       END IF
 
       IF (DFLAG.LT.ZERO) THEN
@@ -236,7 +246,7 @@
          DPARAM(5) = DH22
       ELSE IF (DFLAG.EQ.ZERO) THEN
          DPARAM(3) = DH21
-         DPARAM(4) = DH12 
+         DPARAM(4) = DH12
       ELSE
          DPARAM(2) = DH11
          DPARAM(5) = DH22
@@ -244,8 +254,7 @@
 
       DPARAM(1) = DFLAG
       RETURN
+*
+*     End of DROTMG
+*
       END
-      
-     
-     
-