求助：vensim中方程函数SMOOTH N的问题

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正在学习钟永光著的《系统动力学》，在进行书中例子练习的时候，构建变量的方程式需要用到SMOOTH N函数，而在我的vensim  PLE 5.5中，却没有找到这个函数，只有 SMOOTH、SMOOTH 3和SMOOTH I。请求高手帮助，SMOOTH N函数在哪里，谢谢各位高手了！

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关键词：Vensim smooth vensi SMO sim 求助 方程 函数 Vensim smooth

SMOOTH N(input,delay time, initial value, order) N'th order exponential delay

Returns an N'th order exponential smooth. If order is 1 this function is almost the same as SMOOTHI and if order is 3 it is almost the same as SMOOTH3I.

The SMOOTH N function is treated as a discrete delay function, so that its output is constant for each Time Step. If you are using Euler or Diff integration this is true of all variables. However, if you are using Runge-Kutta integration this is different from functions such as SMOOTH3.

The SMOOTH N function does not conserve quantities. See DELAY N if you want to conserve flows..

Note that for the SMOOTH N function to make sense delay time must be bigger than order* TIME  STEP. If this is not the case Vensim will issue a warning and automatically reduce the order so that this is true. When this happens the behavior of the SMOOTH N function is essentially the same as the behavior of the DELAY INFORMATION function.

Restrictions: SMOOTH N must directly follow the equal sign. It signals Vensim that the variable on the left-hand side of the equation is a Level or State variable. In the Equation Editor select Variable type Level, subtype Delay/Queue and enter SMOOTH N as the function.

Units: SMOOTH N( unit, time unit, unit, dmnl ) --> unit

Examples (12th order Smooth)

perceived quality = SMOOTH N(quality,delay time,quality,12)

2# nkunku

英语对于我来说简直就是外星文字！
在没有求助之前我就看过vensim的帮助文件，但是没有看懂！

自己解决办法：手动输入函数SMOOTH N，虽然在变量选择中没有这个函数，但是在方程中手动输入后，vensim也接受了这个函数，这个应该是内置的函数吧！不知我这样理解是否正确，还望有经验的高手给予指点！

楼主 请教：后来这个问题怎么解决了 就自己输入了 smooth n ？

哥们，你这个问题解决了吗，PLE版本好象只能用smooth求1阶或3阶的函数，其他阶求不了。

In the Equation Editor select Variable type Level, subtype Delay/Queue and enter SMOOTH N as the function.

Units: SMOOTH N( unit, time unit, unit, dmnl ) --> unit

Examples (12th order Smooth)

perceived quality = SMOOTH N(quality,delay time,quality,12)