LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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cdotc.f
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1 *> \brief \b CDOTC
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * COMPLEX FUNCTION CDOTC(N,CX,INCX,CY,INCY)
12 *
13 * .. Scalar Arguments ..
14 * INTEGER INCX,INCY,N
15 * ..
16 * .. Array Arguments ..
17 * COMPLEX CX(*),CY(*)
18 * ..
19 *
20 *
21 *> \par Purpose:
22 * =============
23 *>
24 *> \verbatim
25 *>
26 *> forms the dot product of two vectors, conjugating the first
27 *> vector.
28 *> \endverbatim
29 *
30 * Authors:
31 * ========
32 *
33 *> \author Univ. of Tennessee
34 *> \author Univ. of California Berkeley
35 *> \author Univ. of Colorado Denver
36 *> \author NAG Ltd.
37 *
38 *> \date November 2011
39 *
40 *> \ingroup complex_blas_level1
41 *
42 *> \par Further Details:
43 * =====================
44 *>
45 *> \verbatim
46 *>
47 *> jack dongarra, linpack, 3/11/78.
48 *> modified 12/3/93, array(1) declarations changed to array(*)
49 *> \endverbatim
50 *>
51 * =====================================================================
52  COMPLEX FUNCTION cdotc(N,CX,INCX,CY,INCY)
53 *
54 * -- Reference BLAS level1 routine (version 3.4.0) --
55 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
56 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
57 * November 2011
58 *
59 * .. Scalar Arguments ..
60  INTEGER incx,incy,n
61 * ..
62 * .. Array Arguments ..
63  COMPLEX cx(*),cy(*)
64 * ..
65 *
66 * =====================================================================
67 *
68 * .. Local Scalars ..
69  COMPLEX ctemp
70  INTEGER i,ix,iy
71 * ..
72 * .. Intrinsic Functions ..
73  INTRINSIC conjg
74 * ..
75  ctemp = (0.0,0.0)
76  cdotc = (0.0,0.0)
77  IF (n.LE.0) RETURN
78  IF (incx.EQ.1 .AND. incy.EQ.1) THEN
79 *
80 * code for both increments equal to 1
81 *
82  DO i = 1,n
83  ctemp = ctemp + conjg(cx(i))*cy(i)
84  END DO
85  ELSE
86 *
87 * code for unequal increments or equal increments
88 * not equal to 1
89 *
90  ix = 1
91  iy = 1
92  IF (incx.LT.0) ix = (-n+1)*incx + 1
93  IF (incy.LT.0) iy = (-n+1)*incy + 1
94  DO i = 1,n
95  ctemp = ctemp + conjg(cx(ix))*cy(iy)
96  ix = ix + incx
97  iy = iy + incy
98  END DO
99  END IF
100  cdotc = ctemp
101  RETURN
102  END