Source module last modified on Thu, 2 Jul 1998, 23:17;
HTML image of Fortran source automatically generated by
for2html on Sun, 23 Jun 2002, 15:10.
subroutine csrot (n,cx,incx,cy,incy,c,s)
#
# applies a plane rotation, where the cos and sin (c and s) are real
# and the vectors cx and cy are complex.
# jack dongarra, linpack, 3/11/78.
#
complex cx(1),cy(1),ctemp
real c,s
integer i,incx,incy,ix,iy,n
#
if(n<=0)return
if(incx==1&&incy==1)go to 20
#
# code for unequal increments or equal increments not equal
# to 1
#
ix = 1
iy = 1
if(incx<0)ix = (-n+1)*incx + 1
if(incy<0)iy = (-n+1)*incy + 1
do 10 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
10 continue
return
#
# code for both increments equal to 1
#
20 do 30 i = 1,n
ctemp = c*cx(i) + s*cy(i)
cy(i) = c*cy(i) - s*cx(i)
cx(i) = ctemp
30 continue
return
end