outfile = "coil_diameter_results.txt"
handle=openfile(outfile,"a")
write(handle, "\nComparing various coil diameters \n")
write(handle, "Projectile is 15mm long and 2mm radius\n")
write(handle, "Coil is 20mm long with constant cross-section\n")
write(handle, "Coil inside radius varies:\n")
write(handle, "      2.1, 3.1, 4.1, ..., 30.1mm\n")
write(handle, "To import in Excel:\n")
write(handle, "      Data - Get External Data - Import text file\n")
write(handle, "      then choose the file written by this program\n")
write(handle, "      and click Finish.\n")
write(handle, "This data file is tab delimited\n")
write(handle, "      (Excel's default import format)\n")
closefile(handle)

-- Save the model in temporary file just to be safe
save_femm_file("temp.fem")

-- Set edit mode for selecting and moving projectile (and coil)
-- using simple commands
seteditmode("group")

-- This is how much to increase the coil size between each trial
increment = 1.0
for i=0,27 do
	-- New inner radius is starting size plus how much it has increased
	radius = 2.1 + i*increment

	-- Announce the coil dimensions in the results file
	handle=openfile(outfile,"a")
	write(handle, "\n")
	write(handle, "Coil inside radius = ", radius, " mm\n")
	write(handle, "Coil outside radius = ", radius+3.0, " mm\n")
	write(handle, "\n")
	closefile(handle)

	-- Move the projectile through 40 positions along the axis
	-- and find the force at each spot
	for n=1,40 do
		showmesh()
		analyse()

		-- Pass current position into post-processor
		handle=openfile("tempfile","w")
		pos = n-41
		write(handle, pos)
		closefile(handle)

		runpost("coil_diameter_post.lua")

		-- Nudge projectile another millimeter upward into coil
		selectgroup(1)
		move_translate(0,1)
	end

	-- Move projectile back down to starting position outside coil
	selectgroup(1)
	move_translate(0,-40)

	-- Increase the coil's inner and outer radius
	selectgroup(2)
	move_translate(increment,0)
end
messagebox("All done!")