LAPACK  3.6.1 LAPACK: Linear Algebra PACKage
dzasum.f
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1 *> \brief \b DZASUM
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
12 *
13 * .. Scalar Arguments ..
14 * INTEGER INCX,N
15 * ..
16 * .. Array Arguments ..
17 * COMPLEX*16 ZX(*)
18 * ..
19 *
20 *
21 *> \par Purpose:
22 * =============
23 *>
24 *> \verbatim
25 *>
26 *> DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
27 *> returns a single precision result.
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 2015
39 *
40 *> \ingroup double_blas_level1
41 *
42 *> \par Further Details:
43 * =====================
44 *>
45 *> \verbatim
46 *>
47 *> jack dongarra, 3/11/78.
48 *> modified 3/93 to return if incx .le. 0.
49 *> modified 12/3/93, array(1) declarations changed to array(*)
50 *> \endverbatim
51 *>
52 * =====================================================================
53  DOUBLE PRECISION FUNCTION dzasum(N,ZX,INCX)
54 *
55 * -- Reference BLAS level1 routine (version 3.6.0) --
56 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
57 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
58 * November 2015
59 *
60 * .. Scalar Arguments ..
61  INTEGER INCX,N
62 * ..
63 * .. Array Arguments ..
64  COMPLEX*16 ZX(*)
65 * ..
66 *
67 * =====================================================================
68 *
69 * .. Local Scalars ..
70  DOUBLE PRECISION STEMP
71  INTEGER I,NINCX
72 * ..
73 * .. External Functions ..
74  DOUBLE PRECISION DCABS1
75  EXTERNAL dcabs1
76 * ..
77  dzasum = 0.0d0
78  stemp = 0.0d0
79  IF (n.LE.0 .OR. incx.LE.0) RETURN
80  IF (incx.EQ.1) THEN
81 *
82 * code for increment equal to 1
83 *
84  DO i = 1,n
85  stemp = stemp + dcabs1(zx(i))
86  END DO
87  ELSE
88 *
89 * code for increment not equal to 1
90 *
91  nincx = n*incx
92  DO i = 1,nincx,incx
93  stemp = stemp + dcabs1(zx(i))
94  END DO
95  END IF
96  dzasum = stemp
97  RETURN
98  END
double precision function dzasum(N, ZX, INCX)
DZASUM
Definition: dzasum.f:54