1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
*> \brief \b CSROT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* SUBROUTINE CSROT( N, CX, INCX, CY, INCY, C, S )
*
* .. Scalar Arguments ..
* INTEGER INCX, INCY, N
* REAL C, S
* ..
* .. Array Arguments ..
* COMPLEX CX( * ), CY( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CSROT applies a plane rotation, where the cos and sin (c and s) are real
*> and the vectors cx and cy are complex.
*> jack dongarra, linpack, 3/11/78.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> On entry, N specifies the order of the vectors cx and cy.
*> N must be at least zero.
*> \endverbatim
*>
*> \param[in,out] CX
*> \verbatim
*> CX is COMPLEX array, dimension at least
*> ( 1 + ( N - 1 )*abs( INCX ) ).
*> Before entry, the incremented array CX must contain the n
*> element vector cx. On exit, CX is overwritten by the updated
*> vector cx.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> On entry, INCX specifies the increment for the elements of
*> CX. INCX must not be zero.
*> \endverbatim
*>
*> \param[in,out] CY
*> \verbatim
*> CY is COMPLEX array, dimension at least
*> ( 1 + ( N - 1 )*abs( INCY ) ).
*> Before entry, the incremented array CY must contain the n
*> element vector cy. On exit, CY is overwritten by the updated
*> vector cy.
*> \endverbatim
*>
*> \param[in] INCY
*> \verbatim
*> INCY is INTEGER
*> On entry, INCY specifies the increment for the elements of
*> CY. INCY must not be zero.
*> \endverbatim
*>
*> \param[in] C
*> \verbatim
*> C is REAL
*> On entry, C specifies the cosine, cos.
*> \endverbatim
*>
*> \param[in] S
*> \verbatim
*> S is REAL
*> On entry, S specifies the sine, sin.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date December 2016
*
*> \ingroup complex_blas_level1
*
* =====================================================================
SUBROUTINE CSROT( N, CX, INCX, CY, INCY, C, S )
*
* -- Reference BLAS level1 routine (version 3.7.0) --
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* December 2016
*
* .. Scalar Arguments ..
INTEGER INCX, INCY, N
REAL C, S
* ..
* .. Array Arguments ..
COMPLEX CX( * ), CY( * )
* ..
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, IX, IY
COMPLEX CTEMP
* ..
* .. Executable Statements ..
*
IF( N.LE.0 )
$ RETURN
IF( INCX.EQ.1 .AND. INCY.EQ.1 ) THEN
*
* code for both increments equal to 1
*
DO I = 1, N
CTEMP = C*CX( I ) + S*CY( I )
CY( I ) = C*CY( I ) - S*CX( I )
CX( I ) = CTEMP
END DO
ELSE
*
* code for unequal increments or equal increments not equal
* to 1
*
IX = 1
IY = 1
IF( INCX.LT.0 )
$ IX = ( -N+1 )*INCX + 1
IF( INCY.LT.0 )
$ IY = ( -N+1 )*INCY + 1
DO I = 1, N
CTEMP = C*CX( IX ) + S*CY( IY )
CY( IY ) = C*CY( IY ) - S*CX( IX )
CX( IX ) = CTEMP
IX = IX + INCX
IY = IY + INCY
END DO
END IF
RETURN
END
|
