 LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
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## ◆ 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*