1: *> \brief \b ZDSCAL
2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: * Definition:
9: * ===========
10: *
11: * SUBROUTINE ZDSCAL(N,DA,ZX,INCX)
12: *
13: * .. Scalar Arguments ..
14: * DOUBLE PRECISION DA
15: * INTEGER INCX,N
16: * ..
17: * .. Array Arguments ..
18: * COMPLEX*16 ZX(*)
19: * ..
20: *
21: *
22: *> \par Purpose:
23: * =============
24: *>
25: *> \verbatim
26: *>
27: *> ZDSCAL scales a vector by a constant.
28: *> \endverbatim
29: *
30: * Arguments:
31: * ==========
32: *
33: *> \param[in] N
34: *> \verbatim
35: *> N is INTEGER
36: *> number of elements in input vector(s)
37: *> \endverbatim
38: *>
39: *> \param[in] DA
40: *> \verbatim
41: *> DA is DOUBLE PRECISION
42: *> On entry, DA specifies the scalar alpha.
43: *> \endverbatim
44: *>
45: *> \param[in,out] ZX
46: *> \verbatim
47: *> ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
48: *> \endverbatim
49: *>
50: *> \param[in] INCX
51: *> \verbatim
52: *> INCX is INTEGER
53: *> storage spacing between elements of ZX
54: *> \endverbatim
55: *
56: * Authors:
57: * ========
58: *
59: *> \author Univ. of Tennessee
60: *> \author Univ. of California Berkeley
61: *> \author Univ. of Colorado Denver
62: *> \author NAG Ltd.
63: *
64: *> \ingroup complex16_blas_level1
65: *
66: *> \par Further Details:
67: * =====================
68: *>
69: *> \verbatim
70: *>
71: *> jack dongarra, 3/11/78.
72: *> modified 3/93 to return if incx .le. 0.
73: *> modified 12/3/93, array(1) declarations changed to array(*)
74: *> \endverbatim
75: *>
76: * =====================================================================
77: SUBROUTINE ZDSCAL(N,DA,ZX,INCX)
78: *
79: * -- Reference BLAS level1 routine --
80: * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
81: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
82: *
83: * .. Scalar Arguments ..
84: DOUBLE PRECISION DA
85: INTEGER INCX,N
86: * ..
87: * .. Array Arguments ..
88: COMPLEX*16 ZX(*)
89: * ..
90: *
91: * =====================================================================
92: *
93: * .. Local Scalars ..
94: INTEGER I,NINCX
95: * .. Parameters ..
96: DOUBLE PRECISION ONE
97: PARAMETER (ONE=1.0D+0)
98: * ..
99: * .. Intrinsic Functions ..
100: INTRINSIC DBLE, DCMPLX, DIMAG
101: * ..
102: IF (N.LE.0 .OR. INCX.LE.0 .OR. DA.EQ.ONE) RETURN
103: IF (INCX.EQ.1) THEN
104: *
105: * code for increment equal to 1
106: *
107: DO I = 1,N
108: ZX(I) = DCMPLX(DA*DBLE(ZX(I)),DA*DIMAG(ZX(I)))
109: END DO
110: ELSE
111: *
112: * code for increment not equal to 1
113: *
114: NINCX = N*INCX
115: DO I = 1,NINCX,INCX
116: ZX(I) = DCMPLX(DA*DBLE(ZX(I)),DA*DIMAG(ZX(I)))
117: END DO
118: END IF
119: RETURN
120: *
121: * End of ZDSCAL
122: *
123: END
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