Annotation of rpl/lapack/lapack/dcombssq.f, revision 1.1
1.1 ! bertrand 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
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