/[ascend]/trunk/blas/dcopy.f
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Contents of /trunk/blas/dcopy.f

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Revision 1 - (show annotations) (download)
Fri Oct 29 20:54:12 2004 UTC (15 years, 8 months ago) by aw0a
File size: 1329 byte(s)
Setting up web subdirectory in repository
1 C dcopy.f
2 C is freely available from netlib. It is not subject to any GNU License
3 C set by the authors of the ASCEND math programming system.
4 C $Date: 1996/04/30 18:14:07 $ $Revision: 1.1.1.1 $
5 C
6 subroutine dcopy(n,dx,incx,dy,incy)
7 c
8 c copies a vector, x, to a vector, y.
9 c uses unrolled loops for increments equal to one.
10 c jack dongarra, linpack, 3/11/78.
11 c
12 double precision dx(*),dy(*)
13 integer i,incx,incy,ix,iy,m,mp1,n
14 c
15 if(n.le.0)return
16 if(incx.eq.1.and.incy.eq.1)go to 20
17 c
18 c code for unequal increments or equal increments
19 c not equal to 1
20 c
21 ix = 1
22 iy = 1
23 if(incx.lt.0)ix = (-n+1)*incx + 1
24 if(incy.lt.0)iy = (-n+1)*incy + 1
25 do 10 i = 1,n
26 dy(iy) = dx(ix)
27 ix = ix + incx
28 iy = iy + incy
29 10 continue
30 return
31 c
32 c code for both increments equal to 1
33 c
34 c
35 c clean-up loop
36 c
37 20 m = mod(n,7)
38 if( m .eq. 0 ) go to 40
39 do 30 i = 1,m
40 dy(i) = dx(i)
41 30 continue
42 if( n .lt. 7 ) return
43 40 mp1 = m + 1
44 do 50 i = mp1,n,7
45 dy(i) = dx(i)
46 dy(i + 1) = dx(i + 1)
47 dy(i + 2) = dx(i + 2)
48 dy(i + 3) = dx(i + 3)
49 dy(i + 4) = dx(i + 4)
50 dy(i + 5) = dx(i + 5)
51 dy(i + 6) = dx(i + 6)
52 50 continue
53 return
54 end
55

john.pye@anu.edu.au
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