subroutine radf2(ido, l1, cc, ch, wa1)
use fftpack_kind, only: dp => rk
implicit none
integer, intent(in) :: ido, l1
real(dp), intent(in) :: cc(ido, l1, 2), wa1(*)
real(dp), intent(out) :: ch(ido, 2, l1)
real(dp) :: ti2, tr2
integer :: i, ic, idp2, k
do concurrent(k=1:l1)
ch(1, 1, k) = cc(1, k, 1) + cc(1, k, 2)
ch(ido, 2, k) = cc(1, k, 1) - cc(1, k, 2)
end do
if (ido < 2) return
if (ido /= 2) then
idp2 = ido + 2
do concurrent(k=1:l1, i=3:ido:2)
ic = idp2 - i
tr2 = wa1(i - 2)*cc(i - 1, k, 2) + wa1(i - 1)*cc(i, k, 2)
ti2 = wa1(i - 2)*cc(i, k, 2) - wa1(i - 1)*cc(i - 1, k, 2)
ch(i, 1, k) = cc(i, k, 1) + ti2
ch(ic, 2, k) = ti2 - cc(i, k, 1)
ch(i - 1, 1, k) = cc(i - 1, k, 1) + tr2
ch(ic - 1, 2, k) = cc(i - 1, k, 1) - tr2
end do
if (mod(ido, 2) == 1) return
end if
do concurrent(k=1:l1)
ch(1, 2, k) = -cc(ido, k, 2)
ch(ido, 1, k) = cc(ido, k, 1)
end do
end subroutine radf2
