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From: Mirko on 7 Jun 2010 07:51
Hi to all,
I have this problem.
I have something like this:

[time,states]=ode113(@rates,[0 t_final,[initial_conditions]]);

in rates function i need the current time value at which ode is evaluating the solution because I need it to calculate a value in the rates function.
Is it possible? Is there any way to get it?
From: Mirko on 7 Jun 2010 08:00
"Mirko " <vgsangiuliano(a)gmail.com> wrote in message <huimf8$m4v$1(a)fred.mathworks.com>...
> Hi to all,
> I have this problem.
> I have something like this:
>
> [time,states]=ode113(@rates,[0 t_final,[initial_conditions]]);
>
> in rates function i need the current time value at which ode is evaluating the solution because I need it to calculate a value in the rates function.
> Is it possible? Is there any way to get it?

Sorry I will try to be more precise.
I think i can use the t value in my rates function because my rates function is something like derivatives=rates(t,states)
My problem is that I call other functions inside rates and I don't know how to pass t value from rates to the other funtion.
Thanks
From: Steven Lord on 7 Jun 2010 09:16

"Mirko " <vgsangiuliano(a)gmail.com> wrote in message
news:huin0l$sal$1(a)fred.mathworks.com...
> "Mirko " <vgsangiuliano(a)gmail.com> wrote in message
> <huimf8$m4v$1(a)fred.mathworks.com>...
>> Hi to all,
>> I have this problem.
>> I have something like this:
>>
>> [time,states]=ode113(@rates,[0 t_final,[initial_conditions]]);

You've got a closing square bracket in the wrong place. The time span [0
t_final] is a separate input argument from the initial condition vector;
move the third ] to just after t_final.

>> in rates function i need the current time value at which ode is
>> evaluating the solution because I need it to calculate a value in the
>> rates function.
>> Is it possible? Is there any way to get it?
>
> Sorry I will try to be more precise.
> I think i can use the t value in my rates function because my rates
> function is something like derivatives=rates(t,states)

That is correct; as stated in the help text and documentation, ODE113
requires your ODE function (rates in this case) to accept input arguments t
and y and return y' = f(t, y).

> My problem is that I call other functions inside rates and I don't know
> how to pass t value from rates to the other funtion.

Exactly the same way you'd pass a value to any other function.

function yprime = rates(t, y)
yprime = zeros(size(y));
yprime(1) = myotherfunction(t, y);

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
To contact Technical Support use the Contact Us link on
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