LAPACK  3.6.1 LAPACK: Linear Algebra PACKage
dzsum1.f
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1 *> \brief \b DZSUM1 forms the 1-norm of the complex vector using the true absolute value.
2 *
3 * =========== DOCUMENTATION ===========
4 *
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6 * http://www.netlib.org/lapack/explore-html/
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17 *
18 * Definition:
19 * ===========
20 *
21 * DOUBLE PRECISION FUNCTION DZSUM1( N, CX, INCX )
22 *
23 * .. Scalar Arguments ..
24 * INTEGER INCX, N
25 * ..
26 * .. Array Arguments ..
27 * COMPLEX*16 CX( * )
28 * ..
29 *
30 *
31 *> \par Purpose:
32 * =============
33 *>
34 *> \verbatim
35 *>
36 *> DZSUM1 takes the sum of the absolute values of a complex
37 *> vector and returns a double precision result.
38 *>
39 *> Based on DZASUM from the Level 1 BLAS.
40 *> The change is to use the 'genuine' absolute value.
41 *> \endverbatim
42 *
43 * Arguments:
44 * ==========
45 *
46 *> \param[in] N
47 *> \verbatim
48 *> N is INTEGER
49 *> The number of elements in the vector CX.
50 *> \endverbatim
51 *>
52 *> \param[in] CX
53 *> \verbatim
54 *> CX is COMPLEX*16 array, dimension (N)
55 *> The vector whose elements will be summed.
56 *> \endverbatim
57 *>
58 *> \param[in] INCX
59 *> \verbatim
60 *> INCX is INTEGER
61 *> The spacing between successive values of CX. INCX > 0.
62 *> \endverbatim
63 *
64 * Authors:
65 * ========
66 *
67 *> \author Univ. of Tennessee
68 *> \author Univ. of California Berkeley
69 *> \author Univ. of Colorado Denver
70 *> \author NAG Ltd.
71 *
72 *> \date September 2012
73 *
74 *> \ingroup complex16OTHERauxiliary
75 *
76 *> \par Contributors:
77 * ==================
78 *>
79 *> Nick Higham for use with ZLACON.
80 *
81 * =====================================================================
82  DOUBLE PRECISION FUNCTION dzsum1( N, CX, INCX )
83 *
84 * -- LAPACK auxiliary routine (version 3.4.2) --
85 * -- LAPACK is a software package provided by Univ. of Tennessee, --
86 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
87 * September 2012
88 *
89 * .. Scalar Arguments ..
90  INTEGER INCX, N
91 * ..
92 * .. Array Arguments ..
93  COMPLEX*16 CX( * )
94 * ..
95 *
96 * =====================================================================
97 *
98 * .. Local Scalars ..
99  INTEGER I, NINCX
100  DOUBLE PRECISION STEMP
101 * ..
102 * .. Intrinsic Functions ..
103  INTRINSIC abs
104 * ..
105 * .. Executable Statements ..
106 *
107  dzsum1 = 0.0d0
108  stemp = 0.0d0
109  IF( n.LE.0 )
110  \$ RETURN
111  IF( incx.EQ.1 )
112  \$ GO TO 20
113 *
114 * CODE FOR INCREMENT NOT EQUAL TO 1
115 *
116  nincx = n*incx
117  DO 10 i = 1, nincx, incx
118 *
119 * NEXT LINE MODIFIED.
120 *
121  stemp = stemp + abs( cx( i ) )
122  10 CONTINUE
123  dzsum1 = stemp
124  RETURN
125 *
126 * CODE FOR INCREMENT EQUAL TO 1
127 *
128  20 CONTINUE
129  DO 30 i = 1, n
130 *
131 * NEXT LINE MODIFIED.
132 *
133  stemp = stemp + abs( cx( i ) )
134  30 CONTINUE
135  dzsum1 = stemp
136  RETURN
137 *
138 * End of DZSUM1
139 *
140  END
double precision function dzsum1(N, CX, INCX)
DZSUM1 forms the 1-norm of the complex vector using the true absolute value.
Definition: dzsum1.f:83