回测系统夏普算法

回测系统计算夏普比率的JavaScript源代码如下。

            javascript
            
            
function returnAnalyze(totalAssets, profits, ts, te, period, yearDays) {
    // force by days
    period = 86400000
    if (profits.length == 0) {
        return null
    }
    var freeProfit = 0.03 // 0.04
    var yearRange = yearDays * 86400000
    var totalReturns = profits[profits.length - 1][1] / totalAssets
    var annualizedReturns = (totalReturns * yearRange) / (te - ts)

    // MaxDrawDown
    var maxDrawdown = 0
    var maxAssets = totalAssets
    var maxAssetsTime = 0
    var maxDrawdownTime = 0
    var maxDrawdownStartTime = 0
    var winningRate = 0
    var winningResult = 0
    for (var i = 0; i < profits.length; i++) {
        if (i == 0) {
            if (profits[i][1] > 0) {
                winningResult++
            }
        } else {
            if (profits[i][1] > profits[i - 1][1]) {
                winningResult++
            }
        }
        if ((profits[i][1] + totalAssets) > maxAssets) {
            maxAssets = profits[i][1] + totalAssets
            maxAssetsTime = profits[i][0]
        }
        if (maxAssets > 0) {
            var drawDown = 1 - (profits[i][1] + totalAssets) / maxAssets
            if (drawDown > maxDrawdown) {
                maxDrawdown = drawDown
                maxDrawdownTime = profits[i][0]
                maxDrawdownStartTime = maxAssetsTime
            }
        }
    }
    if (profits.length > 0) {
        winningRate = winningResult / profits.length
    }
    // trim profits
    var i = 0
    var datas = []
    var sum = 0
    var preProfit = 0
    var perRatio = 0
    var rangeEnd = te
    if ((te - ts) % period > 0) {
        rangeEnd = (parseInt(te / period) + 1) * period
    }
    for (var n = ts; n < rangeEnd; n += period) {
        var dayProfit = 0.0
        var cut = n + period
        while (i < profits.length && profits[i][0] < cut) {
            dayProfit += (profits[i][1] - preProfit)
            preProfit = profits[i][1]
            i++
        }
        perRatio = ((dayProfit / totalAssets) * yearRange) / period
        sum += perRatio
        datas.push(perRatio)
    }

    var sharpeRatio = 0
    var volatility = 0
    if (datas.length > 0) {
        var avg = sum / datas.length;
        var std = 0;
        for (i = 0; i < datas.length; i++) {
            std += Math.pow(datas[i] - avg, 2);
        }
        volatility = Math.sqrt(std / datas.length);
        if (volatility !== 0) {
            sharpeRatio = (annualizedReturns - freeProfit) / volatility
        }
    }

    return {
        totalAssets: totalAssets,
        yearDays: yearDays,
        totalReturns: totalReturns,
        annualizedReturns: annualizedReturns,
        sharpeRatio: sharpeRatio,
        volatility: volatility,
        maxDrawdown: maxDrawdown,
        maxDrawdownTime: maxDrawdownTime,
        maxAssetsTime: maxAssetsTime,
        maxDrawdownStartTime: maxDrawdownStartTime,
        winningRate: winningRate
    }
}