LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
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scsum1.f
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1*> \brief \b SCSUM1 forms the 1-norm of the complex vector using the true absolute value.
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/scsum1.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/scsum1.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/scsum1.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18* Definition:
19* ===========
20*
21* REAL FUNCTION SCSUM1( N, CX, INCX )
22*
23* .. Scalar Arguments ..
24* INTEGER INCX, N
25* ..
26* .. Array Arguments ..
27* COMPLEX CX( * )
28* ..
29*
30*
31*> \par Purpose:
32* =============
33*>
34*> \verbatim
35*>
36*> SCSUM1 takes the sum of the absolute values of a complex
37*> vector and returns a single precision result.
38*>
39*> Based on SCASUM 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 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*> \ingroup complexOTHERauxiliary
73*
74*> \par Contributors:
75* ==================
76*>
77*> Nick Higham for use with CLACON.
78*
79* =====================================================================
80 REAL function scsum1( n, cx, incx )
81*
82* -- LAPACK auxiliary routine --
83* -- LAPACK is a software package provided by Univ. of Tennessee, --
84* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
85*
86* .. Scalar Arguments ..
87 INTEGER incx, n
88* ..
89* .. Array Arguments ..
90 COMPLEX cx( * )
91* ..
92*
93* =====================================================================
94*
95* .. Local Scalars ..
96 INTEGER i, nincx
97 REAL stemp
98* ..
99* .. Intrinsic Functions ..
100 INTRINSIC abs
101* ..
102* .. Executable Statements ..
103*
104 scsum1 = 0.0e0
105 stemp = 0.0e0
106 IF( n.LE.0 )
107 \$ RETURN
108 IF( incx.EQ.1 )
109 \$ GO TO 20
110*
111* CODE FOR INCREMENT NOT EQUAL TO 1
112*
113 nincx = n*incx
114 DO 10 i = 1, nincx, incx
115*
116* NEXT LINE MODIFIED.
117*
118 stemp = stemp + abs( cx( i ) )
119 10 CONTINUE
120 scsum1 = stemp
121 RETURN
122*
123* CODE FOR INCREMENT EQUAL TO 1
124*
125 20 CONTINUE
126 DO 30 i = 1, n
127*
128* NEXT LINE MODIFIED.
129*
130 stemp = stemp + abs( cx( i ) )
131 30 CONTINUE
132 scsum1 = stemp
133 RETURN
134*
135* End of SCSUM1
136*
137 END
real function scsum1(N, CX, INCX)
SCSUM1 forms the 1-norm of the complex vector using the true absolute value.
Definition: scsum1.f:81