how to understand and set the constant and boundarycondition properties.

I would like to ask for clarification on how to understand and set the constant and boundarycondition properties. The tutorial mentions: 'We can also set the boundarycondition to true. In that case, species would not be modified by the reactions it participates in, but can still be modified by events, rules, or doses. The constant could be set to true, and in that case, the species can vary during the simulation.' However, I am having some difficulty understanding this concept and how to apply it correctly. Could you please help me clarify?

Answer 1

[Priya Moorthy]

Hi, Michael,

The following post discusses boundary condition vs. constant amount:

https://www.mathworks.com/matlabcentral/answers/528473-what-is-the-difference-between-boundarycondition-and-constantamount?s_tid=answers_rc1-1_p1_MLT

Hope this helps clarify the difference.

Best,

Priya

Answer 2

[Arthur Goldsipe]

If the Constant property of a species is true, then the value of that species cannot change at simulation times > 0. At time = 0, it can only be changed by initial assignment rules and variants.

If the BoundaryCondition property of a species is true, then it is not modified by any reactions it participates in. (Note that if Constant=true, then the value of the BoundaryCondition property is irrelevant.)

A typical case for setting Constant=false and BoundaryCondition=true is if you have a species participating in a reaction, but you want to specify the value of the species some other way. (This specification of the condition is the "boundary condition.")

Take a look at this page for an example.