#!/bin/lua

require 'utils'
require 'mathlib'

function comp(...)
	local s = 'return function (x,y,z) return %s end'
	return assert(loadstring(s:format(...)))()
end

local x1 = 0
local x2 = pi
local p = comp(arg[1] or '-0.5')()
local defh = (x2 - x1) / 1024
local h = comp(arg[4] or defh)()

for x = x1, x2, h do
	y = 1 / (p^2 + 1 + 2*p*cos(x))
	if p < 0 then
		g = y * (p + 1)^2
	else
		g = y * (p - 1)^2
	end
	db = 10*log(g)/log(10)
	print(x, g)
end
printf("p=%f\n", p)