Annotation of rpl/lapack/blas/dzasum.f, revision 1.10
1.8 bertrand 1: *> \brief \b DZASUM
2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: * Definition:
9: * ===========
10: *
11: * DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
12: *
13: * .. Scalar Arguments ..
14: * INTEGER INCX,N
15: * ..
16: * .. Array Arguments ..
17: * COMPLEX*16 ZX(*)
18: * ..
19: *
20: *
21: *> \par Purpose:
22: * =============
23: *>
24: *> \verbatim
25: *>
26: *> DZASUM takes the sum of the absolute values.
27: *> \endverbatim
28: *
29: * Authors:
30: * ========
31: *
32: *> \author Univ. of Tennessee
33: *> \author Univ. of California Berkeley
34: *> \author Univ. of Colorado Denver
35: *> \author NAG Ltd.
36: *
37: *> \date November 2011
38: *
39: *> \ingroup double_blas_level1
40: *
41: *> \par Further Details:
42: * =====================
43: *>
44: *> \verbatim
45: *>
46: *> jack dongarra, 3/11/78.
47: *> modified 3/93 to return if incx .le. 0.
48: *> modified 12/3/93, array(1) declarations changed to array(*)
49: *> \endverbatim
50: *>
51: * =====================================================================
1.1 bertrand 52: DOUBLE PRECISION FUNCTION DZASUM(N,ZX,INCX)
1.8 bertrand 53: *
54: * -- Reference BLAS level1 routine (version 3.4.0) --
55: * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
56: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
57: * November 2011
58: *
1.1 bertrand 59: * .. Scalar Arguments ..
60: INTEGER INCX,N
61: * ..
62: * .. Array Arguments ..
1.8 bertrand 63: COMPLEX*16 ZX(*)
1.1 bertrand 64: * ..
65: *
66: * =====================================================================
67: *
68: * .. Local Scalars ..
69: DOUBLE PRECISION STEMP
1.7 bertrand 70: INTEGER I,NINCX
1.1 bertrand 71: * ..
72: * .. External Functions ..
73: DOUBLE PRECISION DCABS1
74: EXTERNAL DCABS1
75: * ..
76: DZASUM = 0.0d0
77: STEMP = 0.0d0
78: IF (N.LE.0 .OR. INCX.LE.0) RETURN
1.7 bertrand 79: IF (INCX.EQ.1) THEN
1.1 bertrand 80: *
1.7 bertrand 81: * code for increment equal to 1
1.1 bertrand 82: *
1.7 bertrand 83: DO I = 1,N
84: STEMP = STEMP + DCABS1(ZX(I))
85: END DO
86: ELSE
1.1 bertrand 87: *
1.7 bertrand 88: * code for increment not equal to 1
1.1 bertrand 89: *
1.7 bertrand 90: NINCX = N*INCX
91: DO I = 1,NINCX,INCX
92: STEMP = STEMP + DCABS1(ZX(I))
93: END DO
94: END IF
1.1 bertrand 95: DZASUM = STEMP
96: RETURN
97: END
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