Plotting r = r(θ)
The following code is extracted from program simdem64.f95 in the
Simdem package,
and it illustrates how easy it is to plot a curve in the parametric form
r = r(θ), where r and theta are double precision arrays.
!
! calculate r = sin(4*theta)
!
delta = two*pi/dble(n  1)
theta(1) = zero
do i = 2, n  1
theta(i) = theta(i  1) + delta
enddo
theta(n) = two*pi
do i = 1, n
r(i) = sin(four*theta(i))
enddo
!
! plot the 8 leaved rose
!
call rtplot (n, r, theta)
The following plot is then displayed and can be edited to add further
features, printed, or archived as a graphics file.
