Lua ipairs and numeric for test

test_ipairs.lua

-- Changing TABLE_SIZE didn't seem to change much
local TABLE_SIZE          = 10000
local ITERATIONS          = (jit and 100000000 or 10000000) / TABLE_SIZE

local a = {}
for i = 1, TABLE_SIZE do
  a[i] = i * i
end

local sum, start

-- It's possible that the order in which these for tests are executed could
-- tickle LuaJIT to make one or other faster.  I fiddled a bit, but didn't learn
-- anything.

sum = 0
start = os.clock()
for i = 1, ITERATIONS do
  local j = 1
  while true do
    local v = a[j]
    if not v then break end
    sum = sum + j + v
    j = j + 1
  end
end
io.stderr:write("while: ", os.clock() - start, "s, ", sum, "\n")

sum = 0
start = os.clock()
for i = 1, ITERATIONS do
  for j, v in ipairs(a) do
    sum = sum + j + v
  end
end
io.stderr:write("ipairs: ", os.clock() - start, "s, ", sum, "\n")

sum = 0
start = os.clock()
for i = 1, ITERATIONS do
  for j = 1, TABLE_SIZE do
    sum = sum + j + a[j]
  end
end
io.stderr:write("fixed-length numeric_for: ", os.clock() - start, "s, ", sum, "\n")

sum = 0
start = os.clock()
for i = 1, ITERATIONS do
  for j = 1, #a do
    sum = sum + j + a[j]
  end
end
io.stderr:write("numeric_for and #: ", os.clock() - start, "s, ", sum, "\n")