how to solve Coupled equations including ODE and algebraic equations?

All my variables are interdependent. How do I pass extra variables for Ode and algebraic equations?

Answer 1

[Richard Crozier]

Well, the error says it all, you don't define EVI in the function trial.m, it's not passed in as a variable anywhere, and its not declared as a global. Therefore you get an error EVI not defined. Same for VI.

See the docs on ode45 etc. for the standard method of how to pass in extra variables to the ode solvers.

[Urvi]

Thanks! I have an equation for EVI but all my equations are inter related hence I dont understand how to incorporate that into my code.

[Richard Crozier]

When you call ode45 you can do things with anonymous functions like:

EVI = 0;
VI = i490324023;
sol = ode45(@(t,y) myfun(t,y,EVI,VI), tspan, initconds);

Look up anonymous functions for more info.

[Richard Crozier]

By the way, you should have left the question as it was, now others looking up the same question won't understand the answer. Start a new question for a new (better defined) problem.

[Urvi]

ya sure. Thanks!