To know the units of t span used in ode45 command

I am using ODE45 command to solve 8 ordinary differential equations. My doubt is if im specifying tspan=[0 1000] , what will be the units of time like is it in seconds, minutes, hours?

code:

tspan=[0 1000];

yo=[1;2;3;4;5;6;7;8;9];

[tsol,ysol]=ode45(@filename,tspan,yo];

[James Tursa]

The units of tspan is dictated by how you formulate your differential equation in the function handle. ode45( ) doesn't assume or know anything about units.

[Saraswathi S]

Thank you so much Sir

Answer 1

[Yongjian Feng]

You can type this in the matlab command line window:

help ode45

to get help for ode45 function.

The first input argument is a function handler. This is the function that tells you what t means. In other words, whatever unit of t is used in the function handler, it is also used in the tspan.

Does it make sense?

Thanks,

Yongjian

[Saraswathi S]

Yes, Thank you so much Sir

Answer 2

[Steven Lord]

There is no unit inherent to the t variable used by ode45. Just implement your ODE function correctly for your time units.

If you're solving a physics problem and using standard gravity you should formulate it in seconds.

If you were modeling a predator-prey system using the Lotka-Volterra equations then your time units would probably be years.

[Saraswathi S]

Okay Sir. Thank you so much.