csrotf.f

subroutinecsrotf (n,cx,incx,cy,incy,c,s)
c
c applies a plane rotation, where the cos and sin (c and s) are real
c and the vectors cx and cy are complex.
c jack dongarra, linpack, 3/11/78.
c
complex cx(1),cy(1),ctemp
real c,s
integer i,incx,incy,ix,iy,n
c
if(n.le.0)return
if(incx.eq.1.and.incy.eq.1)go to20
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
do10 i =1,n
 ctemp = c*cx(ix) + s*cy(iy)
 cy(iy) = c*cy(iy) - s*cx(ix)
 cx(ix) = ctemp
 ix = ix + incx
 iy = iy + incy
10continue
return
c
c code for both increments equal to 1
c
20do30 i =1,n
 ctemp = c*cx(i) + s*cy(i)
 cy(i) = c*cy(i) - s*cx(i)
 cx(i) = ctemp
30continue
return
end