/[ascend]/trunk/blas/dcopy.f
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Fri Oct 29 20:54:12 2004 UTC (15 years, 3 months ago) by aw0a
File size: 1329 byte(s)
Setting up web subdirectory in repository
1 aw0a 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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