1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
subroutine srot (n,sx,incx,sy,incy,c,s)
c
c applies a plane rotation.
c jack dongarra, linpack, 3/11/78.
c
real sx(1),sy(1),stemp,c,s
integer i,incx,incy,ix,iy,n
c
if(n.le.0)return
if(incx.eq.1.and.incy.eq.1)go to 20
c
c code for unequal increments or equal increments not equal
c to 1
c
ix = 1
iy = 1
if(incx.lt.0)ix = (-n+1)*incx + 1
if(incy.lt.0)iy = (-n+1)*incy + 1
do 10 i = 1,n
stemp = c*sx(ix) + s*sy(iy)
sy(iy) = c*sy(iy) - s*sx(ix)
sx(ix) = stemp
ix = ix + incx
iy = iy + incy
10 continue
return
c
c code for both increments equal to 1
c
20 do 30 i = 1,n
stemp = c*sx(i) + s*sy(i)
sy(i) = c*sy(i) - s*sx(i)
sx(i) = stemp
30 continue
return
end
|
