LAPACK  3.9.0
LAPACK: Linear Algebra PACKage

◆ dlartv()

subroutine dlartv ( integer  N,
double precision, dimension( * )  X,
integer  INCX,
double precision, dimension( * )  Y,
integer  INCY,
double precision, dimension( * )  C,
double precision, dimension( * )  S,
integer  INCC 
)

DLARTV applies a vector of plane rotations with real cosines and real sines to the elements of a pair of vectors.

Download DLARTV + dependencies [TGZ] [ZIP] [TXT]

Purpose:
 DLARTV applies a vector of real plane rotations to elements of the
 real vectors x and y. For i = 1,2,...,n

    ( x(i) ) := (  c(i)  s(i) ) ( x(i) )
    ( y(i) )    ( -s(i)  c(i) ) ( y(i) )
Parameters
[in]N
          N is INTEGER
          The number of plane rotations to be applied.
[in,out]X
          X is DOUBLE PRECISION array,
                         dimension (1+(N-1)*INCX)
          The vector x.
[in]INCX
          INCX is INTEGER
          The increment between elements of X. INCX > 0.
[in,out]Y
          Y is DOUBLE PRECISION array,
                         dimension (1+(N-1)*INCY)
          The vector y.
[in]INCY
          INCY is INTEGER
          The increment between elements of Y. INCY > 0.
[in]C
          C is DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
          The cosines of the plane rotations.
[in]S
          S is DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
          The sines of the plane rotations.
[in]INCC
          INCC is INTEGER
          The increment between elements of C and S. INCC > 0.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date
December 2016

Definition at line 110 of file dlartv.f.

110 *
111 * -- LAPACK auxiliary routine (version 3.7.0) --
112 * -- LAPACK is a software package provided by Univ. of Tennessee, --
113 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
114 * December 2016
115 *
116 * .. Scalar Arguments ..
117  INTEGER INCC, INCX, INCY, N
118 * ..
119 * .. Array Arguments ..
120  DOUBLE PRECISION C( * ), S( * ), X( * ), Y( * )
121 * ..
122 *
123 * =====================================================================
124 *
125 * .. Local Scalars ..
126  INTEGER I, IC, IX, IY
127  DOUBLE PRECISION XI, YI
128 * ..
129 * .. Executable Statements ..
130 *
131  ix = 1
132  iy = 1
133  ic = 1
134  DO 10 i = 1, n
135  xi = x( ix )
136  yi = y( iy )
137  x( ix ) = c( ic )*xi + s( ic )*yi
138  y( iy ) = c( ic )*yi - s( ic )*xi
139  ix = ix + incx
140  iy = iy + incy
141  ic = ic + incc
142  10 CONTINUE
143  RETURN
144 *
145 * End of DLARTV
146 *
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