LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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◆ scsum1()

real function scsum1 ( integer  N,
complex, dimension( * )  CX,
integer  INCX 
)

SCSUM1 forms the 1-norm of the complex vector using the true absolute value.

Download SCSUM1 + dependencies [TGZ] [ZIP] [TXT]

Purpose:
 SCSUM1 takes the sum of the absolute values of a complex
 vector and returns a single precision result.

 Based on SCASUM 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 array, dimension (N)
          The vector whose elements will be summed.
[in]INCX
          INCX is INTEGER
          The spacing between successive values of CX.  INCX > 0.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Contributors:
Nick Higham for use with CLACON.

Definition at line 80 of file scsum1.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 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*
real function scsum1(N, CX, INCX)
SCSUM1 forms the 1-norm of the complex vector using the true absolute value.
Definition: scsum1.f:81
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