1*> \brief \b DCOPY
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 DCOPY(N,DX,INCX,DY,INCY)
12*
13*       .. Scalar Arguments ..
14*       INTEGER INCX,INCY,N
15*       ..
16*       .. Array Arguments ..
17*       DOUBLE PRECISION DX(*),DY(*)
18*       ..
19*
20*
21*> \par Purpose:
22*  =============
23*>
24*> \verbatim
25*>
26*>    DCOPY copies a vector, x, to a vector, y.
27*>    uses unrolled loops for increments equal to one.
28*> \endverbatim
29*
30*  Authors:
31*  ========
32*
33*> \author Univ. of Tennessee
34*> \author Univ. of California Berkeley
35*> \author Univ. of Colorado Denver
36*> \author NAG Ltd.
37*
38*> \date November 2011
39*
40*> \ingroup double_blas_level1
41*
42*> \par Further Details:
43*  =====================
44*>
45*> \verbatim
46*>
47*>     jack dongarra, linpack, 3/11/78.
48*>     modified 12/3/93, array(1) declarations changed to array(*)
49*> \endverbatim
50*>
51*  =====================================================================
52      SUBROUTINE DCOPY(N,DX,INCX,DY,INCY)
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*
59*     .. Scalar Arguments ..
60      INTEGER INCX,INCY,N
61*     ..
62*     .. Array Arguments ..
63      DOUBLE PRECISION DX(*),DY(*)
64*     ..
65*
66*  =====================================================================
67*
68*     .. Local Scalars ..
69      INTEGER I,IX,IY,M,MP1
70*     ..
71*     .. Intrinsic Functions ..
72      INTRINSIC MOD
73*     ..
74      IF (N.LE.0) RETURN
75      IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
76*
77*        code for both increments equal to 1
78*
79*
80*        clean-up loop
81*
82         M = MOD(N,7)
83         IF (M.NE.0) THEN
84            DO I = 1,M
85               DY(I) = DX(I)
86            END DO
87            IF (N.LT.7) RETURN
88         END IF
89         MP1 = M + 1
90         DO I = MP1,N,7
91            DY(I) = DX(I)
92            DY(I+1) = DX(I+1)
93            DY(I+2) = DX(I+2)
94            DY(I+3) = DX(I+3)
95            DY(I+4) = DX(I+4)
96            DY(I+5) = DX(I+5)
97            DY(I+6) = DX(I+6)
98         END DO
99      ELSE
100*
101*        code for unequal increments or equal increments
102*          not equal to 1
103*
104         IX = 1
105         IY = 1
106         IF (INCX.LT.0) IX = (-N+1)*INCX + 1
107         IF (INCY.LT.0) IY = (-N+1)*INCY + 1
108         DO I = 1,N
109            DY(IY) = DX(IX)
110            IX = IX + INCX
111            IY = IY + INCY
112         END DO
113      END IF
114      RETURN
115      END
116