如何获取账户风险度？

跑模拟账户，风险度控制不了。代码如下：Params Numeric MaxRiskRatio(0.6); Vars Series<Numeric> LastEquity; // 最新权益 Series<Numeric> FreeMargin; // 可用资金 Series<Numeric> UsedMargin; Series<Numeric> CurrentRiskRatio; Account acc; Events OnReady() { Bool ret = A_GetAccount(acc, "66133512"); CurrentRiskRatio = acc.available/acc.lastAmount; } OnBar(ArrayRef<Integer> indexs) { Commentary("CurrentRiskRatio:" + Text(CurrentRiskRatio)); FreeMargin = Portfolio_CurrentCapital(); UsedMargin = Portfolio_UsedMargin(); LastEquity = FreeMargin + UsedMargin; If (LastEquity > 0) { CurrentRiskRatio = UsedMargin / LastEquity; } Else { CurrentRiskRatio = 1; } Commentary("LastEquity:" + Text(LastEquity)); Commentary("CurrentRiskRatio:" + Text(CurrentRiskRatio)); Commentary("acc.available:" + Text(acc.available)); //If(CurrentRiskRatio <= MaxRiskRatio) 开仓 }请问，哪里出了问题？谢谢！