LÖVE

Code: Select all

	function lcg(s, r)
		local temp = {}
		function temp:random(a, b)
			local y = mod(self.a * self.x + self.c, self.m)
			self.x = y
			if not a then
				return y / 65536
			elseif not b then
				if a == 0 then
					return y
				else
					return 1 + mod(y, a)
				end
			else
				return a + mod(y, b - a + 1)
			end
		end
		function temp:randomseed(s)
			if not s then
				s = seed()
			end
			self.x = mod(s, 2147483648)
		end
		if r then
			--from Numerical Recipes
			if r == 'nr' then
				temp.a = 1664525
				temp.c = 1013904223
				temp.m = 65536
			--from MVC
			elseif r == 'mvc' then
				temp.a = 214013
				temp.c = 2531011
				temp.m = 65536
			end
		--from Ansi C
		else
			temp.a = 1103515245
			temp.c = 12345
			temp.m = 65536
		end
		temp:randomseed(s)
		return temp
	end

	print("wutwut =" .. lcg(0):random())
	print("wutwut =" .. lcg(0):random())
	print("wutwut =" .. lcg(0):random())

Code: Select all

local gen = lcg(0)
print("wutwut =" .. gen:random())
print("wutwut =" .. gen:random())
print("wutwut =" .. gen:random())

Code: Select all

function TestLuaNumberFormat()
	local dbl = 2 ^ 53
	local flt = 2 ^ 24
	local int32 = 1073741823 * 2 + 1
	local uint32 = 1073741823 * 4 + 3
	local int64 = (1073741823 * 131072 + 131071) * 65536 + 65535
	local uint64 = (1073741823 * 131072 + 131071) * 131072 + 131071

	local fmt
	if dbl ~= dbl - 1 and dbl == dbl + 1 then
		fmt = "double-precision floating-point number"
	elseif flt ~= flt - 1 and flt == flt + 1 then
		fmt = "single-precision floating-point number"
	elseif int32 > 0 and int32 + 1 < 0 then
		fmt = "signed 32-bit integer"
	elseif uint32 > 0 and uint32 + 1 == 0 and uint32 + 2 == 1 then
		fmt = "unsigned 32-bit integer"
	elseif int64 > 0 and int64 + 1 < 0 then
		fmt = "signed 64-bit integer"
	elseif uint64 > 0 and uint64 + 1 == 0 and uint64 + 2 == 1 then
		fmt = "unsigned 64-bit integer"
	end

	if fmt then
		print("Feels like " .. fmt .. ".")
	else
		print("Unkown format.")
	end
end

Code: Select all

function mul16(a, b)
	local a_lo, b_lo = mod(a, 2^8), mod(b, 2^8)
	local a_hi, b_hi = a - a_lo, b - b_lo

	return mod(a_lo * b_lo + mod(a_lo * b_hi, 2^16) + mod(a_hi * b_lo, 2^16) + mod(a_hi * b_hi, 2^16), 2^16)
end

function lcg(s, r)
	local temp = {}
	function temp:random(a, b)
		local y = mod(mul16(self.a, self.x) + self.c, self.m)
		self.x = y
		if not a then
			return y / 65536
		elseif not b then
			if a == 0 then
				return y
			else
				return 1 + mod(y, a)
			end
		else
			return a + mod(y, b - a + 1)
		end
	end
	function temp:randomseed(s)
		if not s then
			s = seed()
		end
		self.x = mod(s, 2147483648)
	end

	-- 'Numerical Recipes' parameters
	temp.a = 26125
	temp.c = 62303
	temp.m = 65536

	temp:randomseed(s)
	return temp
end

Code: Select all

local my_seed_1 = {977322}

function srandom(seedobj, fVal1, fVal2)
	seedobj[1] = mod(seedobj[1] * 1103515245 + 12345, 4294967296)
	local temp_rand = seedobj[1] / (4294967296 - 1)
	if (fVal2) then
		return floor(fVal1 + 0.5 + temp_rand * (fVal2 - fVal1))
	elseif (fVal1) then
		return floor(temp_rand * fVal1) + 1
	else
		return temp_rand
	end
end

print(srandom(my_seed_1))