LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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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 double precision result.
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,out] ZX
40*> \verbatim
41*> ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
42*> \endverbatim
43*>
44*> \param[in] INCX
45*> \verbatim
46*> INCX is INTEGER
47*> storage spacing between elements of ZX
48*> \endverbatim
49*
50* Authors:
51* ========
52*
53*> \author Univ. of Tennessee
54*> \author Univ. of California Berkeley
55*> \author Univ. of Colorado Denver
56*> \author NAG Ltd.
57*
58*> \ingroup double_blas_level1
59*
60*> \par Further Details:
61* =====================
62*>
63*> \verbatim
64*>
65*> jack dongarra, 3/11/78.
66*> modified 3/93 to return if incx .le. 0.
67*> modified 12/3/93, array(1) declarations changed to array(*)
68*> \endverbatim
69*>
70* =====================================================================
71 DOUBLE PRECISION FUNCTION dzasum(N,ZX,INCX)
72*
73* -- Reference BLAS level1 routine --
74* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
75* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
76*
77* .. Scalar Arguments ..
78 INTEGER incx,n
79* ..
80* .. Array Arguments ..
81 COMPLEX*16 zx(*)
82* ..
83*
84* =====================================================================
85*
86* .. Local Scalars ..
87 DOUBLE PRECISION stemp
88 INTEGER i,nincx
89* ..
90* .. External Functions ..
91 DOUBLE PRECISION dcabs1
92 EXTERNAL dcabs1
93* ..
94 dzasum = 0.0d0
95 stemp = 0.0d0
96 IF (n.LE.0 .OR. incx.LE.0) RETURN
97 IF (incx.EQ.1) THEN
98*
99* code for increment equal to 1
100*
101 DO i = 1,n
102 stemp = stemp + dcabs1(zx(i))
103 END DO
104 ELSE
105*
106* code for increment not equal to 1
107*
108 nincx = n*incx
109 DO i = 1,nincx,incx
110 stemp = stemp + dcabs1(zx(i))
111 END DO
112 END IF
113 dzasum = stemp
114 RETURN
115*
116* End of DZASUM
117*
118 END
double precision function dcabs1(Z)
DCABS1
Definition: dcabs1.f:47
double precision function dzasum(N, ZX, INCX)
DZASUM
Definition: dzasum.f:72