LAPACK  3.7.1
LAPACK: Linear Algebra PACKage
zaxpy.f
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1 *> \brief \b ZAXPY
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 ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
12 *
13 * .. Scalar Arguments ..
14 * COMPLEX*16 ZA
15 * INTEGER INCX,INCY,N
16 * ..
17 * .. Array Arguments ..
18 * COMPLEX*16 ZX(*),ZY(*)
19 * ..
20 *
21 *
22 *> \par Purpose:
23 * =============
24 *>
25 *> \verbatim
26 *>
27 *> ZAXPY 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] ZA
40 *> \verbatim
41 *> ZA is COMPLEX*16
42 *> On entry, ZA specifies the scalar alpha.
43 *> \endverbatim
44 *>
45 *> \param[in] ZX
46 *> \verbatim
47 *> ZX is COMPLEX*16 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 ZX
54 *> \endverbatim
55 *>
56 *> \param[in,out] ZY
57 *> \verbatim
58 *> ZY is COMPLEX*16 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 ZY
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 *> \date December 2016
76 *
77 *> \ingroup complex16_blas_level1
78 *
79 *> \par Further Details:
80 * =====================
81 *>
82 *> \verbatim
83 *>
84 *> jack dongarra, 3/11/78.
85 *> modified 12/3/93, array(1) declarations changed to array(*)
86 *> \endverbatim
87 *>
88 * =====================================================================
89  SUBROUTINE zaxpy(N,ZA,ZX,INCX,ZY,INCY)
90 *
91 * -- Reference BLAS level1 routine (version 3.7.0) --
92 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
93 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
94 * December 2016
95 *
96 * .. Scalar Arguments ..
97  COMPLEX*16 ZA
98  INTEGER INCX,INCY,N
99 * ..
100 * .. Array Arguments ..
101  COMPLEX*16 ZX(*),ZY(*)
102 * ..
103 *
104 * =====================================================================
105 *
106 * .. Local Scalars ..
107  INTEGER I,IX,IY
108 * ..
109 * .. External Functions ..
110  DOUBLE PRECISION DCABS1
111  EXTERNAL dcabs1
112 * ..
113  IF (n.LE.0) RETURN
114  IF (dcabs1(za).EQ.0.0d0) RETURN
115  IF (incx.EQ.1 .AND. incy.EQ.1) THEN
116 *
117 * code for both increments equal to 1
118 *
119  DO i = 1,n
120  zy(i) = zy(i) + za*zx(i)
121  END DO
122  ELSE
123 *
124 * code for unequal increments or equal increments
125 * not equal to 1
126 *
127  ix = 1
128  iy = 1
129  IF (incx.LT.0) ix = (-n+1)*incx + 1
130  IF (incy.LT.0) iy = (-n+1)*incy + 1
131  DO i = 1,n
132  zy(iy) = zy(iy) + za*zx(ix)
133  ix = ix + incx
134  iy = iy + incy
135  END DO
136  END IF
137 *
138  RETURN
139  END
subroutine zaxpy(N, ZA, ZX, INCX, ZY, INCY)
ZAXPY
Definition: zaxpy.f:90