LAPACK  3.10.0 LAPACK: Linear Algebra PACKage
caxpy.f
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1 *> \brief \b CAXPY
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * SUBROUTINE CAXPY(N,CA,CX,INCX,CY,INCY)
12 *
13 * .. Scalar Arguments ..
14 * COMPLEX CA
15 * INTEGER INCX,INCY,N
16 * ..
17 * .. Array Arguments ..
18 * COMPLEX CX(*),CY(*)
19 * ..
20 *
21 *
22 *> \par Purpose:
23 * =============
24 *>
25 *> \verbatim
26 *>
27 *> CAXPY constant times a vector plus a vector.
28 *> \endverbatim
29 *
30 * Arguments:
31 * ==========
32 *
33 *> \param[in] N
34 *> \verbatim
35 *> N is INTEGER
36 *> number of elements in input vector(s)
37 *> \endverbatim
38 *>
39 *> \param[in] CA
40 *> \verbatim
41 *> CA is COMPLEX
42 *> On entry, CA specifies the scalar alpha.
43 *> \endverbatim
44 *>
45 *> \param[in] CX
46 *> \verbatim
47 *> CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
48 *> \endverbatim
49 *>
50 *> \param[in] INCX
51 *> \verbatim
52 *> INCX is INTEGER
53 *> storage spacing between elements of CX
54 *> \endverbatim
55 *>
56 *> \param[in,out] CY
57 *> \verbatim
58 *> CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
59 *> \endverbatim
60 *>
61 *> \param[in] INCY
62 *> \verbatim
63 *> INCY is INTEGER
64 *> storage spacing between elements of CY
65 *> \endverbatim
66 *
67 * Authors:
68 * ========
69 *
70 *> \author Univ. of Tennessee
71 *> \author Univ. of California Berkeley
72 *> \author Univ. of Colorado Denver
73 *> \author NAG Ltd.
74 *
75 *> \ingroup complex_blas_level1
76 *
77 *> \par Further Details:
78 * =====================
79 *>
80 *> \verbatim
81 *>
82 *> jack dongarra, linpack, 3/11/78.
83 *> modified 12/3/93, array(1) declarations changed to array(*)
84 *> \endverbatim
85 *>
86 * =====================================================================
87  SUBROUTINE caxpy(N,CA,CX,INCX,CY,INCY)
88 *
89 * -- Reference BLAS level1 routine --
90 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
91 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
92 *
93 * .. Scalar Arguments ..
94  COMPLEX CA
95  INTEGER INCX,INCY,N
96 * ..
97 * .. Array Arguments ..
98  COMPLEX CX(*),CY(*)
99 * ..
100 *
101 * =====================================================================
102 *
103 * .. Local Scalars ..
104  INTEGER I,IX,IY
105 * ..
106 * .. External Functions ..
107  REAL SCABS1
108  EXTERNAL scabs1
109 * ..
110  IF (n.LE.0) RETURN
111  IF (scabs1(ca).EQ.0.0e+0) RETURN
112  IF (incx.EQ.1 .AND. incy.EQ.1) THEN
113 *
114 * code for both increments equal to 1
115 *
116  DO i = 1,n
117  cy(i) = cy(i) + ca*cx(i)
118  END DO
119  ELSE
120 *
121 * code for unequal increments or equal increments
122 * not equal to 1
123 *
124  ix = 1
125  iy = 1
126  IF (incx.LT.0) ix = (-n+1)*incx + 1
127  IF (incy.LT.0) iy = (-n+1)*incy + 1
128  DO i = 1,n
129  cy(iy) = cy(iy) + ca*cx(ix)
130  ix = ix + incx
131  iy = iy + incy
132  END DO
133  END IF
134 *
135  RETURN
136 *
137 * End of CAXPY
138 *
139  END
subroutine caxpy(N, CA, CX, INCX, CY, INCY)
CAXPY
Definition: caxpy.f:88