how to model change between two time steps

[Omogbai]

Hello all,
What equation can be written for an auxiliary variable (A) that is the result of another variable (B) when the state changes from time Tx to time Tx+1, such that,
A at time Tx+1 = B at time Tx+1 minus B at time Tx
I am trying to model the change between the simulated data generated in two consecutive time steps.
Thanks
omo

[Administrator]

I don't understand "A at time Tx+1 = B at time Tx+1 minus B at time Tx".

But it looks like you need a simple IF THEN ELSE statement.

[Omogbai]

thanks for your response
assuming my units of time is in months. and i want to represent the change in a variable between month 1 and 2. This change needs to be used as an equation for another variable.

[Administrator]

Sorry, I just don't understand what you are asking for help with.

[JdX33]

Hello everyone,

I don't have the answer but I think I'm facing the same problem and I'll try to make it understandable.

I want to model the evolution of an auxiliary variable with the simulation time.
For example : I have one auxiliary variable "A" , a second auxiliary variable "B" and another auxiliary variable "C". Let's say C= A*TIME + B (basic y=ax+b equation) so the value of my auxiliary variable "C" will vary for each time step of the simulation (obviously the STEP function will not be useful in this case).

How to use the time as a variable such as presented in my example ?

Thank you in advance and sorry if my question seems stupid !

J.

[LAUJJL]

Hi

In your equation C varies with the Time and not with each time step, that is generally constant.

The time is a variable that can be used in all équations.

I join a simple model that answers too the first question about how to calculate the change in a variable.

Regards.

JJ