LAPACK  3.4.2 LAPACK: Linear Algebra PACKage
dlartv.f
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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 *
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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 *> \date September 2012
105 *
106 *> \ingroup doubleOTHERauxiliary
107 *
108 * =====================================================================
109  SUBROUTINE dlartv( N, X, INCX, Y, INCY, C, S, INCC )
110 *
111 * -- LAPACK auxiliary routine (version 3.4.2) --
112 * -- LAPACK is a software package provided by Univ. of Tennessee, --
113 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
114 * September 2012
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 *
147  END