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第137行： − + − To get intermediate values and better accuracy, the model can run in continuous time: we multiply the number of units of time and we proportionally divide values that change stock levels. In this example we multiply the 15 years by 4 to obtain 60 trimesters, and we divide the value of the flow by 4.<br>+ − To get intermediate values and better accuracy, the model can run in continuous time: we multiply the number of units of time and we proportionally divide values that change stock levels. In this example we multiply the 15 years by 4 to obtain 60 trimesters, and we divide the value of the flow by 4.<br> − − 为了得到中间值和更好的准确性，该模型可以在连续时间内运行: 我们乘以时间单位的数量，并按比例除以改变存量水平的值。在这个例子中，我们把15年乘以4得到60个三个月，然后我们把流量的值除以4。 Br − − Dividing the value is the simplest with the [[Euler method]], but other methods could be employed instead, such as [[Runge–Kutta methods]]. − − Dividing the value is the simplest with the Euler method, but other methods could be employed instead, such as Runge–Kutta methods. − − − − List of the equations in continuous time for trimesters = 1 to 60 : − − List of the equations in continuous time for trimesters = 1 to 60 : − + − − − − <math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math> − − <math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math> − − 10) mbox { Valve New adopters } mbox { New adopters } cdot TimeStep / math − − <math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math> − − <math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math> − − 数学10.1) mbox { Potential adopters } - mbox { Valve New adopters } / math − − <math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math> − − <math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math> − − 10.2) mbox { Adopters } mbox { Valve New Adopters } / math − − − − − − <math> \ TimeStep = 1/4 </math> − − <math> \ TimeStep = 1/4 </math> − − 数学 time step 1 / 4 / math − − − + − *In the below stock and flow diagram, the intermediate flow 'Valve New adopters' calculates the equation :+ + + − <math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math> − <math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math>+ − + − + +
→连续时间方程 Equations in continuous time
[[Image:SFDD VAL.gif|centre|年存量和流量值=0至15|frame]]
[[Image:SFDD VAL.gif|centre|年存量和流量值=0至15|frame]]
===连续时间方程 Equations in continuous time===
===连续时间方程===
为了得到中间值和更好的准确性，该模型可以在连续时间内运行: 我们乘以时间单位的数量，并按比例除以改变存量水平的值。在这个例子中，我们把15年乘以4得到60个三个月，然后我们把流量的值除以4。
用欧拉法除值是最简单的方法，但也可以用其他方法代替，如龙格-库塔法。
用欧拉法除值是最简单的方法，但也可以用其他方法代替，如龙格-库塔法。
连续时间方程列表1至60的三个月:
连续时间方程列表1至60的三个月:
*They are the same equations as in the section ''Equation in discrete time'' above, except equations ''4.1'' and ''4.2'' replaced by following :
*除将式4.1和式4.2替换为以下形式外，与上述“离散时间方程”一节相同:
<math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math>
<math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math>
<math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math>
<math> \ TimeStep = 1/4 </math>
*在下面的库存和流程图中，中间流''Valve新采用者''计算公式:
{ Valve New adopters } mbox { New adopters } cdot TimeStep / math
<math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math>
[[Image:Adaption SFD continuous time.png|centre|Dynamic stock and flow diagram of ''New product adoption'' model in continuous time|frame]]
[[Image:Adaption SFD continuous time.png|centre|连续时间下“新产品采用”模型的动态库存及流程图|frame]]
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