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

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Revision 1 - (show annotations) (download)
Fri Oct 29 20:54:12 2004 UTC (15 years, 7 months ago) by aw0a
File size: 1089 byte(s)
Setting up web subdirectory in repository
1 C dscal.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: 1998/04/25 14:18:09 $ $Revision: 1.2 $
5 C
6 subroutine dscal(n,da,dx,incx)
7 c
8 c scales a vector dx by a constant da.
9 c uses unrolled loops for increment equal to one.
10 c jack dongarra, linpack, 3/11/78.
11 c
12 double precision da,dx(*)
13 integer i,incx,m,mp1,n,nincx
14 c
15 if(n.le.0)return
16 if(incx.eq.1)go to 20
17 c
18 c code for increment not equal to 1
19 c
20 nincx = n*incx
21 do 10 i = 1,nincx,incx
22 dx(i) = da*dx(i)
23 10 continue
24 return
25 c
26 c code for increment equal to 1
27 c
28 c
29 c clean-up loop
30 c
31 20 m = mod(n,5)
32 if( m .eq. 0 ) go to 40
33 do 30 i = 1,m
34 dx(i) = da*dx(i)
35 30 continue
36 if( n .lt. 5 ) return
37 40 mp1 = m + 1
38 do 50 i = mp1,n,5
39 dx(i) = da*dx(i)
40 dx(i + 1) = da*dx(i + 1)
41 dx(i + 2) = da*dx(i + 2)
42 dx(i + 3) = da*dx(i + 3)
43 dx(i + 4) = da*dx(i + 4)
44 50 continue
45 return
46 end
47

john.pye@anu.edu.au
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