How to evaluate a cell of function handles?

Hi,

suppose that we have cell arrays of function handles Rnum, for example:

fnum=matlabFunction(y);
Fnum=@(x)integral(fnum,0,x);
Rnum{i,:}=@(x) exp(-(Fnum(x)).^beta_hat(i,:));

with i-number of different beta_hats. y is a function which consists of i-number of symbolic variables.

Now, I would like to evaluate all functions at the points: x = 0:100:4000.

Does anyone know how it works?

PS: If I do it for only one point x = 400, I can use the following code which works very well: cellfun(@(c) c(x),Rnum).

Answer 1

[Kirby Fears]

Max,

If your function handles can accept an array of x values and return an array of results, then your current implementation works fine. It would look like this:

x = 0:100:4000;
resultsCell = cellfun(@(c) c(x),Rnum,'UniformOutput',false);

Otherwise you can use arrayfun or a loop to go over the different x values. A loop might actually be easier to read:

x = 0:100:4000;
resultCell = cell(numel(x),1);
for xval = 1:numel(x),
    resultCell{xval} = cellfun(@(c) c(x(xval)),Rnum);
end

The arrayfun approach would look like this:

resultCell = ...
  arrayfun(@(xval) cellfun(@(c) c(xval),Rnum),x,'UniformOutput',false);

Hope this helps.

[Max]

Hey Kirby, thnx for your solution. Now, it works very well. That´s exactly what I was searching for.

Answer 2

[Rebecca Krosnick]

Using the "cellfun" function as you have pointed out is a good way to apply a function to each cell in a cell array.

If you would like to call the function on multiple input points x, then you should either call "cellfun" for each x value, or change your implementation of your function c such that it will take as an argument the vector 0:100:4000 and produces the appropriate results.