Annotation of rpl/lapack/blas/dzasum.f, revision 1.14
1.8 bertrand 1: *> \brief \b DZASUM
2: *
3: * =========== DOCUMENTATION ===========
4: *
1.14 ! bertrand 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
1.8 bertrand 7: *
8: * Definition:
9: * ===========
10: *
11: * DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.14 ! bertrand 12: *
1.8 bertrand 13: * .. Scalar Arguments ..
14: * INTEGER INCX,N
15: * ..
16: * .. Array Arguments ..
17: * COMPLEX*16 ZX(*)
18: * ..
1.14 ! bertrand 19: *
1.8 bertrand 20: *
21: *> \par Purpose:
22: * =============
23: *>
24: *> \verbatim
25: *>
1.12 bertrand 26: *> DZASUM takes the sum of the (|Re(.)| + |Im(.)|)'s of a complex vector and
27: *> returns a single precision result.
1.8 bertrand 28: *> \endverbatim
29: *
30: * Authors:
31: * ========
32: *
1.14 ! bertrand 33: *> \author Univ. of Tennessee
! 34: *> \author Univ. of California Berkeley
! 35: *> \author Univ. of Colorado Denver
! 36: *> \author NAG Ltd.
1.8 bertrand 37: *
1.14 ! bertrand 38: *> \date December 2016
1.8 bertrand 39: *
40: *> \ingroup double_blas_level1
41: *
42: *> \par Further Details:
43: * =====================
44: *>
45: *> \verbatim
46: *>
47: *> jack dongarra, 3/11/78.
48: *> modified 3/93 to return if incx .le. 0.
49: *> modified 12/3/93, array(1) declarations changed to array(*)
50: *> \endverbatim
51: *>
52: * =====================================================================
1.1 bertrand 53: DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.8 bertrand 54: *
1.14 ! bertrand 55: * -- Reference BLAS level1 routine (version 3.7.0) --
1.8 bertrand 56: * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
57: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.14 ! bertrand 58: * December 2016
1.8 bertrand 59: *
1.1 bertrand 60: * .. Scalar Arguments ..
61: INTEGER INCX,N
62: * ..
63: * .. Array Arguments ..
1.8 bertrand 64: COMPLEX*16 ZX(*)
1.1 bertrand 65: * ..
66: *
67: * =====================================================================
68: *
69: * .. Local Scalars ..
70: DOUBLE PRECISION STEMP
1.7 bertrand 71: INTEGER I,NINCX
1.1 bertrand 72: * ..
73: * .. External Functions ..
74: DOUBLE PRECISION DCABS1
75: EXTERNAL DCABS1
76: * ..
77: DZASUM = 0.0d0
78: STEMP = 0.0d0
79: IF (N.LE.0 .OR. INCX.LE.0) RETURN
1.7 bertrand 80: IF (INCX.EQ.1) THEN
1.1 bertrand 81: *
1.7 bertrand 82: * code for increment equal to 1
1.1 bertrand 83: *
1.7 bertrand 84: DO I = 1,N
85: STEMP = STEMP + DCABS1(ZX(I))
86: END DO
87: ELSE
1.1 bertrand 88: *
1.7 bertrand 89: * code for increment not equal to 1
1.1 bertrand 90: *
1.7 bertrand 91: NINCX = N*INCX
92: DO I = 1,NINCX,INCX
93: STEMP = STEMP + DCABS1(ZX(I))
94: END DO
95: END IF
1.1 bertrand 96: DZASUM = STEMP
97: RETURN
98: END
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