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    1: *> \brief \b DCOMBSSQ adds two scaled sum of squares quantities.
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *
    9: *  Definition:
   10: *  ===========
   11: *
   12: *       SUBROUTINE DCOMBSSQ( V1, V2 )
   13: *
   14: *       .. Array Arguments ..
   15: *       DOUBLE PRECISION   V1( 2 ), V2( 2 )
   16: *       ..
   17: *
   18: *
   19: *> \par Purpose:
   20: *  =============
   21: *>
   22: *> \verbatim
   23: *>
   24: *> DCOMBSSQ adds two scaled sum of squares quantities, V1 := V1 + V2.
   25: *> That is,
   26: *>
   27: *>    V1_scale**2 * V1_sumsq := V1_scale**2 * V1_sumsq
   28: *>                            + V2_scale**2 * V2_sumsq
   29: *> \endverbatim
   30: *
   31: *  Arguments:
   32: *  ==========
   33: *
   34: *> \param[in,out] V1
   35: *> \verbatim
   36: *>          V1 is DOUBLE PRECISION array, dimension (2).
   37: *>          The first scaled sum.
   38: *>          V1(1) = V1_scale, V1(2) = V1_sumsq.
   39: *> \endverbatim
   40: *>
   41: *> \param[in] V2
   42: *> \verbatim
   43: *>          V2 is DOUBLE PRECISION array, dimension (2).
   44: *>          The second scaled sum.
   45: *>          V2(1) = V2_scale, V2(2) = V2_sumsq.
   46: *> \endverbatim
   47: *
   48: *  Authors:
   49: *  ========
   50: *
   51: *> \author Univ. of Tennessee
   52: *> \author Univ. of California Berkeley
   53: *> \author Univ. of Colorado Denver
   54: *> \author NAG Ltd.
   55: *
   56: *> \date November 2018
   57: *
   58: *> \ingroup OTHERauxiliary
   59: *
   60: *  =====================================================================
   61:       SUBROUTINE DCOMBSSQ( V1, V2 )
   62: *
   63: *  -- LAPACK auxiliary routine (version 3.7.0) --
   64: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
   65: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   66: *     November 2018
   67: *
   68: *     .. Array Arguments ..
   69:       DOUBLE PRECISION   V1( 2 ), V2( 2 )
   70: *     ..
   71: *
   72: * =====================================================================
   73: *
   74: *     .. Parameters ..
   75:       DOUBLE PRECISION   ZERO
   76:       PARAMETER          ( ZERO = 0.0D+0 )
   77: *     ..
   78: *     .. Executable Statements ..
   79: *
   80:       IF( V1( 1 ).GE.V2( 1 ) ) THEN
   81:          IF( V1( 1 ).NE.ZERO ) THEN
   82:             V1( 2 ) = V1( 2 ) + ( V2( 1 ) / V1( 1 ) )**2 * V2( 2 )
   83:          END IF
   84:       ELSE
   85:          V1( 2 ) = V2( 2 ) + ( V1( 1 ) / V2( 1 ) )**2 * V1( 2 )
   86:          V1( 1 ) = V2( 1 )
   87:       END IF
   88:       RETURN
   89: *
   90: *     End of DCOMBSSQ
   91: *
   92:       END