LAPACK  3.10.0
LAPACK: Linear Algebra PACKage

◆ dzasum()

double precision function dzasum ( integer  N,
complex*16, dimension(*)  ZX,
integer  INCX 
)

DZASUM

Purpose:
    DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
    returns a double precision result.
Parameters
[in]N
          N is INTEGER
         number of elements in input vector(s)
[in,out]ZX
          ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
[in]INCX
          INCX is INTEGER
         storage spacing between elements of ZX
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
     jack dongarra, 3/11/78.
     modified 3/93 to return if incx .le. 0.
     modified 12/3/93, array(1) declarations changed to array(*)

Definition at line 71 of file dzasum.f.

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 *
double precision function dcabs1(Z)
DCABS1
Definition: dcabs1.f:47
double precision function dzasum(N, ZX, INCX)
DZASUM
Definition: dzasum.f:72
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