benchmarking lua elsif vs hashtable

elseif_lookup_sequential.lua

local nBranch = 1
local nLoops = 2000000

print("NUMBER_BRANCHS,TIME_ELSEIF,TIME_LOOKUP")
while (nBranch <= 100) do
	io.write(nBranch)
	io.write(",")
	local valueName = "iInner"
	local elseifCodeTable = {"local iOutter = 1\nwhile iOutter <= " .. nLoops .. " do\n\tlocal iInner = 1\n\tlocal dummy;\n\twhile iInner <= " .. nBranch .. " do\n", "\t\tend\n\t\tiInner = iInner + 1\n\tend\n\tiOutter = iOutter + 1\nend"}
	local i = 1

	while (i <= nBranch) do
		if i ~= 1 then
			table.insert(elseifCodeTable, #elseifCodeTable, string.format("\t\telseif %s == %i then\n\t\t\t dummy = true\n", valueName, i))
		else
			table.insert(elseifCodeTable, #elseifCodeTable, string.format("\t\tif %s == 1 then\n\t\t\t dummy = true\n", valueName))
		end

		i = i + 1
	end


	local elseifFunction, err = loadstring(table.concat(elseifCodeTable))


	if not elseifFunction then error(err) end

	local time = os.clock()
	elseifFunction()
	io.write(os.clock() - time)
	io.write(",")
	local lookupTable = {}
	i = 1

	while (i <= nBranch) do
		lookupTable[i] = true
		i = i + 1
	end
	local function lookUpFunction()
		local iOutter = 1

		while (iOutter <= nLoops) do
			local iInner = 1

			while iInner <= nBranch do
				local dummy = lookupTable[iInner]
				iInner = iInner + 1
			end

			iOutter = iOutter + 1
		end
	end

	time = os.clock()
	lookUpFunction()
	io.write(os.clock() - time)
	io.write("\n")
	nBranch = nBranch + 1
end

PUC_Lua Graph