--- rpl/lapack/blas/drotg.f	2010/08/07 13:22:08	1.4
+++ rpl/lapack/blas/drotg.f	2014/01/27 09:28:12	1.11
@@ -1,17 +1,59 @@
-      SUBROUTINE DROTG(DA,DB,C,S)
-*     .. Scalar Arguments ..
-      DOUBLE PRECISION C,DA,DB,S
-*     ..
+*> \brief \b DROTG
+*
+*  =========== DOCUMENTATION ===========
 *
-*  Purpose
-*  =======
+* Online html documentation available at 
+*            http://www.netlib.org/lapack/explore-html/ 
 *
-*     DROTG construct givens plane rotation.
+*  Definition:
+*  ===========
+*
+*       SUBROUTINE DROTG(DA,DB,C,S)
+* 
+*       .. Scalar Arguments ..
+*       DOUBLE PRECISION C,DA,DB,S
+*       ..
+*  
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*>    DROTG construct givens plane rotation.
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee 
+*> \author Univ. of California Berkeley 
+*> \author Univ. of Colorado Denver 
+*> \author NAG Ltd. 
+*
+*> \date November 2011
+*
+*> \ingroup double_blas_level1
+*
+*> \par Further Details:
+*  =====================
+*>
+*> \verbatim
+*>
+*>     jack dongarra, linpack, 3/11/78.
+*> \endverbatim
+*>
+*  =====================================================================
+      SUBROUTINE DROTG(DA,DB,C,S)
 *
-*  Further Details
-*  ===============
+*  -- Reference BLAS level1 routine (version 3.4.0) --
+*  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
+*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+*     November 2011
 *
-*     jack dongarra, linpack, 3/11/78.
+*     .. Scalar Arguments ..
+      DOUBLE PRECISION C,DA,DB,S
+*     ..
 *
 *  =====================================================================
 *
@@ -24,20 +66,21 @@
       ROE = DB
       IF (DABS(DA).GT.DABS(DB)) ROE = DA
       SCALE = DABS(DA) + DABS(DB)
-      IF (SCALE.NE.0.0d0) GO TO 10
-      C = 1.0d0
-      S = 0.0d0
-      R = 0.0d0
-      Z = 0.0d0
-      GO TO 20
-   10 R = SCALE*DSQRT((DA/SCALE)**2+ (DB/SCALE)**2)
-      R = DSIGN(1.0d0,ROE)*R
-      C = DA/R
-      S = DB/R
-      Z = 1.0d0
-      IF (DABS(DA).GT.DABS(DB)) Z = S
-      IF (DABS(DB).GE.DABS(DA) .AND. C.NE.0.0d0) Z = 1.0d0/C
-   20 DA = R
+      IF (SCALE.EQ.0.0d0) THEN
+         C = 1.0d0
+         S = 0.0d0
+         R = 0.0d0
+         Z = 0.0d0
+      ELSE
+         R = SCALE*DSQRT((DA/SCALE)**2+ (DB/SCALE)**2)
+         R = DSIGN(1.0d0,ROE)*R
+         C = DA/R
+         S = DB/R
+         Z = 1.0d0
+         IF (DABS(DA).GT.DABS(DB)) Z = S
+         IF (DABS(DB).GE.DABS(DA) .AND. C.NE.0.0d0) Z = 1.0d0/C
+      END IF
+      DA = R
       DB = Z
       RETURN
       END