Lua补偿求和：浮点累加的误差治理

-- 错误：浮点直接逐条累加，误差单向滚动
local total = 0
for _, v in ipairs(hits) do
    total = total + v
end

local function kahanSum(list)
    local sum, comp = 0, 0
    for _, v in ipairs(list) do
        local y = v - comp
        local t = sum + y
        comp = (t - sum) - y
        sum = t
    end
    return sum
end
local hits = {}
for _ = 1, 100000 do
    hits[#hits + 1] = 0.1
end
local label = panel:getChildByName("sumText")
label:setString(string.format("%.6f", kahanSum(hits)))