95 lines
2.2 KiB
Fortran
95 lines
2.2 KiB
Fortran
*> \brief \b SCOMBSSQ adds two scaled sum of squares quantities
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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*
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* Definition:
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* ===========
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*
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* SUBROUTINE SCOMBSSQ( V1, V2 )
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*
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* .. Array Arguments ..
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* REAL V1( 2 ), V2( 2 )
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* ..
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*
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*
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*> \par Purpose:
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* =============
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*>
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*> \verbatim
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*>
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*> SCOMBSSQ adds two scaled sum of squares quantities, V1 := V1 + V2.
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*> That is,
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*>
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*> V1_scale**2 * V1_sumsq := V1_scale**2 * V1_sumsq
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*> + V2_scale**2 * V2_sumsq
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*> \endverbatim
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*
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* Arguments:
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* ==========
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*
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*> \param[in,out] V1
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*> \verbatim
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*> V1 is REAL array, dimension (2).
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*> The first scaled sum.
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*> V1(1) = V1_scale, V1(2) = V1_sumsq.
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*> \endverbatim
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*>
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*> \param[in] V2
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*> \verbatim
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*> V2 is REAL array, dimension (2).
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*> The second scaled sum.
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*> V2(1) = V2_scale, V2(2) = V2_sumsq.
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*> \endverbatim
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*
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* Authors:
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* ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \date November 2018
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*
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*> \ingroup OTHERauxiliary
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*
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* =====================================================================
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SUBROUTINE SCOMBSSQ( V1, V2 )
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*
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* -- LAPACK auxiliary routine (version 3.7.0) --
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* -- LAPACK is a software package provided by Univ. of Tennessee, --
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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* November 2018
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*
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* .. Array Arguments ..
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REAL V1( 2 ), V2( 2 )
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* ..
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*
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* =====================================================================
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*
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* .. Parameters ..
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REAL ZERO
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PARAMETER ( ZERO = 0.0D+0 )
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* ..
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* .. Executable Statements ..
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*
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IF( V1( 1 ).GE.V2( 1 ) ) THEN
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IF( V1( 1 ).NE.ZERO ) THEN
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V1( 2 ) = V1( 2 ) + ( V2( 1 ) / V1( 1 ) )**2 * V2( 2 )
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ELSE
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V1( 2 ) = V1( 2 ) + V2( 2 )
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END IF
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ELSE
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V1( 2 ) = V2( 2 ) + ( V1( 1 ) / V2( 1 ) )**2 * V1( 2 )
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V1( 1 ) = V2( 1 )
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END IF
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RETURN
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*
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* End of SCOMBSSQ
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*
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END
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