Create an array of n function handle

Hello,

How can I create a set of ode equations?

Example:

fun1 = @(t,x,k) x-k;

I want to generate a function of n entries like:

funN = @(t,x,k) [ x(1)-k
                 x(2)-k
                 ...
                 x(n)-k ];

I want to run the program for different values of n, so I can't create the full function handle bu hand.

Thanks.

Answer 1

[Guillaume]

I'm not sure why your anonymous functions take a t input that they don't use. Anyway:

funN = @(~, x, k, N) reshape(x(1:N) - k, [], 1);

and to create a cell array of them:

N = 10; %for example
allfuns = arrayfun(@(n) @(t, x, k) funN(t, x, k, n), 1:N, 'UniformOutput', false);

[Felix Lauwaert]

t is necessary to solve odes with ode45, even if it's an autonomous one.

Unfortunately, I fail at undersanding your solution. Do I have to write all three lines one under the other?

If I do so, I get this error:

 Undefined function 'exist' for input arguments
 of type 'cell'.

 Error in odearguments (line 59)
  if (exist(ode)==2)

Thanks.

[Guillaume]

I answered the title of your question (how to create an array of n functions handles) but I missed the subquestion (how can I create a set of ODE equations).

As far as I know, you cannot pass an array of function handles to the ODE solvers, you have to give them a single function to solve. Hence, why you're getting the error. The ODE did not expect a cell array.

However, I'm unclear on exactly what you want to solve. To solve for one n value, you'd use only one of the allfuns function:

n = 5; %for example
ode45(allfuns{5}, ...)

%or without bothering with the cell array:
ode45(@(t, x, k) funN(t, x, k, n), ...)