Editing System dynamics (section)

===Equations in continuous time===
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 quarters, and we divide the value of the flow by 4.<br>
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 :
*They are the same equations as in the section ''Equation in discrete time'' above, except equations ''4.1'' and ''4.2'' replaced by following :
 <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>

*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>
[[Image:Adaption SFD continuous time.png|centre|Dynamic stock and flow diagram of ''New product adoption'' model in continuous time|frame]]