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*> \brief \b SLAR2V applies a vector of plane rotations with real cosines and real sines from both sides to a sequence of 2-by-2 symmetric/Hermitian matrices.
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download SLAR2V + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slar2v.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slar2v.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slar2v.f">
*> [TXT]</a>
*> \endhtmlonly
*
* Definition:
* ===========
*
* SUBROUTINE SLAR2V( N, X, Y, Z, INCX, C, S, INCC )
*
* .. Scalar Arguments ..
* INTEGER INCC, INCX, N
* ..
* .. Array Arguments ..
* REAL C( * ), S( * ), X( * ), Y( * ), Z( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> SLAR2V applies a vector of real plane rotations from both sides to
*> a sequence of 2-by-2 real symmetric matrices, defined by the elements
*> of the vectors x, y and z. For i = 1,2,...,n
*>
*> ( x(i) z(i) ) := ( c(i) s(i) ) ( x(i) z(i) ) ( c(i) -s(i) )
*> ( z(i) y(i) ) ( -s(i) c(i) ) ( z(i) y(i) ) ( s(i) c(i) )
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The number of plane rotations to be applied.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is REAL array,
*> dimension (1+(N-1)*INCX)
*> The vector x.
*> \endverbatim
*>
*> \param[in,out] Y
*> \verbatim
*> Y is REAL array,
*> dimension (1+(N-1)*INCX)
*> The vector y.
*> \endverbatim
*>
*> \param[in,out] Z
*> \verbatim
*> Z is REAL array,
*> dimension (1+(N-1)*INCX)
*> The vector z.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The increment between elements of X, Y and Z. INCX > 0.
*> \endverbatim
*>
*> \param[in] C
*> \verbatim
*> C is REAL array, dimension (1+(N-1)*INCC)
*> The cosines of the plane rotations.
*> \endverbatim
*>
*> \param[in] S
*> \verbatim
*> S is REAL array, dimension (1+(N-1)*INCC)
*> The sines of the plane rotations.
*> \endverbatim
*>
*> \param[in] INCC
*> \verbatim
*> INCC is INTEGER
*> The increment between elements of C and S. INCC > 0.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \ingroup lar2v
*
* =====================================================================
SUBROUTINE SLAR2V( N, X, Y, Z, INCX, C, S, INCC )
*
* -- LAPACK auxiliary routine --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
* .. Scalar Arguments ..
INTEGER INCC, INCX, N
* ..
* .. Array Arguments ..
REAL C( * ), S( * ), X( * ), Y( * ), Z( * )
* ..
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, IC, IX
REAL CI, SI, T1, T2, T3, T4, T5, T6, XI, YI, ZI
* ..
* .. Executable Statements ..
*
IX = 1
IC = 1
DO 10 I = 1, N
XI = X( IX )
YI = Y( IX )
ZI = Z( IX )
CI = C( IC )
SI = S( IC )
T1 = SI*ZI
T2 = CI*ZI
T3 = T2 - SI*XI
T4 = T2 + SI*YI
T5 = CI*XI + T1
T6 = CI*YI - T1
X( IX ) = CI*T5 + SI*T4
Y( IX ) = CI*T6 - SI*T3
Z( IX ) = CI*T4 - SI*T5
IX = IX + INCX
IC = IC + INCC
10 CONTINUE
*
* End of SLAR2V
*
RETURN
END
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