Return to dlartv.f CVS log

Up to [local] / rpl / lapack / lapack

Annotation of rpl/lapack/lapack/dlartv.f, revision 1.18

1.11      bertrand    1: *> \brief \b DLARTV applies a vector of plane rotations with real cosines and real sines to the elements of a pair of vectors.
1.8       bertrand    2: *
                      3: *  =========== DOCUMENTATION ===========
                      4: *
1.15      bertrand    5: * Online html documentation available at
                      6: *            http://www.netlib.org/lapack/explore-html/
1.8       bertrand    7: *
                      8: *> \htmlonly
1.15      bertrand    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">
1.8       bertrand   15: *> [TXT]</a>
1.15      bertrand   16: *> \endhtmlonly
1.8       bertrand   17: *
                     18: *  Definition:
                     19: *  ===========
                     20: *
                     21: *       SUBROUTINE DLARTV( N, X, INCX, Y, INCY, C, S, INCC )
1.15      bertrand   22: *
1.8       bertrand   23: *       .. Scalar Arguments ..
                     24: *       INTEGER            INCC, INCX, INCY, N
                     25: *       ..
                     26: *       .. Array Arguments ..
                     27: *       DOUBLE PRECISION   C( * ), S( * ), X( * ), Y( * )
                     28: *       ..
1.15      bertrand   29: *
1.8       bertrand   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: *
1.15      bertrand   99: *> \author Univ. of Tennessee
                    100: *> \author Univ. of California Berkeley
                    101: *> \author Univ. of Colorado Denver
                    102: *> \author NAG Ltd.
1.8       bertrand  103: *
                    104: *> \ingroup doubleOTHERauxiliary
                    105: *
                    106: *  =====================================================================
1.1       bertrand  107:       SUBROUTINE DLARTV( N, X, INCX, Y, INCY, C, S, INCC )
                    108: *
1.18    ! bertrand  109: *  -- LAPACK auxiliary routine --
1.1       bertrand  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