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 1.
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] DX
40*> \verbatim
41*>          DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
42*> \endverbatim
43*>
44*> \param[in] INCX
45*> \verbatim
46*>          INCX is INTEGER
47*>         storage spacing between elements of DX
48*> \endverbatim
49*>
50*> \param[out] DY
51*> \verbatim
52*>          DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
53*> \endverbatim
54*>
55*> \param[in] INCY
56*> \verbatim
57*>          INCY is INTEGER
58*>         storage spacing between elements of DY
59*> \endverbatim
60*
61*  Authors:
62*  ========
63*
64*> \author Univ. of Tennessee
65*> \author Univ. of California Berkeley
66*> \author Univ. of Colorado Denver
67*> \author NAG Ltd.
68*
69*> \ingroup double_blas_level1
70*
71*> \par Further Details:
72*  =====================
73*>
74*> \verbatim
75*>
76*>     jack dongarra, linpack, 3/11/78.
77*>     modified 12/3/93, array(1) declarations changed to array(*)
78*> \endverbatim
79*>
80*  =====================================================================
81      SUBROUTINE DCOPY(N,DX,INCX,DY,INCY)
82*
83*  -- Reference BLAS level1 routine --
84*  -- Reference BLAS is a software package provided by Univ. of Tennessee,    --
85*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
86*
87*     .. Scalar Arguments ..
88      INTEGER INCX,INCY,N
89*     ..
90*     .. Array Arguments ..
91      DOUBLE PRECISION DX(*),DY(*)
92*     ..
93*
94*  =====================================================================
95*
96*     .. Local Scalars ..
97      INTEGER I,IX,IY,M,MP1
98*     ..
99*     .. Intrinsic Functions ..
100      INTRINSIC MOD
101*     ..
102      IF (N.LE.0) RETURN
103      IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
104*
105*        code for both increments equal to 1
106*
107*
108*        clean-up loop
109*
110         M = MOD(N,7)
111         IF (M.NE.0) THEN
112            DO I = 1,M
113               DY(I) = DX(I)
114            END DO
115            IF (N.LT.7) RETURN
116         END IF
117         MP1 = M + 1
118         DO I = MP1,N,7
119            DY(I) = DX(I)
120            DY(I+1) = DX(I+1)
121            DY(I+2) = DX(I+2)
122            DY(I+3) = DX(I+3)
123            DY(I+4) = DX(I+4)
124            DY(I+5) = DX(I+5)
125            DY(I+6) = DX(I+6)
126         END DO
127      ELSE
128*
129*        code for unequal increments or equal increments
130*          not equal to 1
131*
132         IX = 1
133         IY = 1
134         IF (INCX.LT.0) IX = (-N+1)*INCX + 1
135         IF (INCY.LT.0) IY = (-N+1)*INCY + 1
136         DO I = 1,N
137            DY(IY) = DX(IX)
138            IX = IX + INCX
139            IY = IY + INCY
140         END DO
141      END IF
142      RETURN
143*
144*     End of DCOPY
145*
146      END
147