LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
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## ◆ dzsum1()

 double precision function dzsum1 ( integer N, complex*16, dimension( * ) CX, integer INCX )

DZSUM1 forms the 1-norm of the complex vector using the true absolute value.

Purpose:
``` DZSUM1 takes the sum of the absolute values of a complex
vector and returns a double precision result.

Based on DZASUM from the Level 1 BLAS.
The change is to use the 'genuine' absolute value.```
Parameters
 [in] N ``` N is INTEGER The number of elements in the vector CX.``` [in] CX ``` CX is COMPLEX*16 array, dimension (N) The vector whose elements will be summed.``` [in] INCX ``` INCX is INTEGER The spacing between successive values of CX. INCX > 0.```
Contributors:
Nick Higham for use with ZLACON.

Definition at line 80 of file dzsum1.f.

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*16 CX( * )
91* ..
92*
93* =====================================================================
94*
95* .. Local Scalars ..
96 INTEGER I, NINCX
97 DOUBLE PRECISION STEMP
98* ..
99* .. Intrinsic Functions ..
100 INTRINSIC abs
101* ..
102* .. Executable Statements ..
103*
104 dzsum1 = 0.0d0
105 stemp = 0.0d0
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 dzsum1 = 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 dzsum1 = stemp
133 RETURN
134*
135* End of DZSUM1
136*
double precision function dzsum1(N, CX, INCX)
DZSUM1 forms the 1-norm of the complex vector using the true absolute value.
Definition: dzsum1.f:81
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