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    1: *> \brief \b DLARTV applies a vector of plane rotations with real cosines and real sines to the elements of a pair of vectors.
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *> \htmlonly
    9: *> Download DLARTV + dependencies
   10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlartv.f">
   11: *> [TGZ]</a>
   12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlartv.f">
   13: *> [ZIP]</a>
   14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlartv.f">
   15: *> [TXT]</a>
   16: *> \endhtmlonly
   17: *
   18: *  Definition:
   19: *  ===========
   20: *
   21: *       SUBROUTINE DLARTV( N, X, INCX, Y, INCY, C, S, INCC )
   22: *
   23: *       .. Scalar Arguments ..
   24: *       INTEGER            INCC, INCX, INCY, N
   25: *       ..
   26: *       .. Array Arguments ..
   27: *       DOUBLE PRECISION   C( * ), S( * ), X( * ), Y( * )
   28: *       ..
   29: *
   30: *
   31: *> \par Purpose:
   32: *  =============
   33: *>
   34: *> \verbatim
   35: *>
   36: *> DLARTV applies a vector of real plane rotations to elements of the
   37: *> real vectors x and y. For i = 1,2,...,n
   38: *>
   39: *>    ( x(i) ) := (  c(i)  s(i) ) ( x(i) )
   40: *>    ( y(i) )    ( -s(i)  c(i) ) ( y(i) )
   41: *> \endverbatim
   42: *
   43: *  Arguments:
   44: *  ==========
   45: *
   46: *> \param[in] N
   47: *> \verbatim
   48: *>          N is INTEGER
   49: *>          The number of plane rotations to be applied.
   50: *> \endverbatim
   51: *>
   52: *> \param[in,out] X
   53: *> \verbatim
   54: *>          X is DOUBLE PRECISION array,
   55: *>                         dimension (1+(N-1)*INCX)
   56: *>          The vector x.
   57: *> \endverbatim
   58: *>
   59: *> \param[in] INCX
   60: *> \verbatim
   61: *>          INCX is INTEGER
   62: *>          The increment between elements of X. INCX > 0.
   63: *> \endverbatim
   64: *>
   65: *> \param[in,out] Y
   66: *> \verbatim
   67: *>          Y is DOUBLE PRECISION array,
   68: *>                         dimension (1+(N-1)*INCY)
   69: *>          The vector y.
   70: *> \endverbatim
   71: *>
   72: *> \param[in] INCY
   73: *> \verbatim
   74: *>          INCY is INTEGER
   75: *>          The increment between elements of Y. INCY > 0.
   76: *> \endverbatim
   77: *>
   78: *> \param[in] C
   79: *> \verbatim
   80: *>          C is DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
   81: *>          The cosines of the plane rotations.
   82: *> \endverbatim
   83: *>
   84: *> \param[in] S
   85: *> \verbatim
   86: *>          S is DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
   87: *>          The sines of the plane rotations.
   88: *> \endverbatim
   89: *>
   90: *> \param[in] INCC
   91: *> \verbatim
   92: *>          INCC is INTEGER
   93: *>          The increment between elements of C and S. INCC > 0.
   94: *> \endverbatim
   95: *
   96: *  Authors:
   97: *  ========
   98: *
   99: *> \author Univ. of Tennessee
  100: *> \author Univ. of California Berkeley
  101: *> \author Univ. of Colorado Denver
  102: *> \author NAG Ltd.
  103: *
  104: *> \ingroup doubleOTHERauxiliary
  105: *
  106: *  =====================================================================
  107:       SUBROUTINE DLARTV( N, X, INCX, Y, INCY, C, S, INCC )
  108: *
  109: *  -- LAPACK auxiliary routine --
  110: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
  111: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
  112: *
  113: *     .. Scalar Arguments ..
  114:       INTEGER            INCC, INCX, INCY, N
  115: *     ..
  116: *     .. Array Arguments ..
  117:       DOUBLE PRECISION   C( * ), S( * ), X( * ), Y( * )
  118: *     ..
  119: *
  120: *  =====================================================================
  121: *
  122: *     .. Local Scalars ..
  123:       INTEGER            I, IC, IX, IY
  124:       DOUBLE PRECISION   XI, YI
  125: *     ..
  126: *     .. Executable Statements ..
  127: *
  128:       IX = 1
  129:       IY = 1
  130:       IC = 1
  131:       DO 10 I = 1, N
  132:          XI = X( IX )
  133:          YI = Y( IY )
  134:          X( IX ) = C( IC )*XI + S( IC )*YI
  135:          Y( IY ) = C( IC )*YI - S( IC )*XI
  136:          IX = IX + INCX
  137:          IY = IY + INCY
  138:          IC = IC + INCC
  139:    10 CONTINUE
  140:       RETURN
  141: *
  142: *     End of DLARTV
  143: *
  144:       END