 LAPACK  3.10.0 LAPACK: Linear Algebra PACKage

## ◆ dcopy()

 subroutine dcopy ( integer N, double precision, dimension(*) DX, integer INCX, double precision, dimension(*) DY, integer INCY )

DCOPY

Purpose:
```    DCOPY copies a vector, x, to a vector, y.
uses unrolled loops for increments equal to 1.```
Parameters
 [in] N ``` N is INTEGER number of elements in input vector(s)``` [in] DX ` DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )` [in] INCX ``` INCX is INTEGER storage spacing between elements of DX``` [out] DY ` DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) )` [in] INCY ``` INCY is INTEGER storage spacing between elements of DY```
Further Details:
```     jack dongarra, linpack, 3/11/78.
modified 12/3/93, array(1) declarations changed to array(*)```

Definition at line 81 of file dcopy.f.

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 *