Vectorized or single line evaluation of function array in MATLAB

Question

In a previous question, a user asked about iterating over a cell array of anonymous functions. I am wondering whether there is a way to evaluate a set of functions without the explicit use of a for loop.

As an example, the following code creates an array of (simple) functions, evaluates them for a fixed value and stores the results:

fcnList = {@(x) (x+1), @(x) (x+2)};
a = 2;
for i = 1:numel(fcnList)
    y(i) = fcnList{i}(a);
end

Is there a way to do this without looping?

Answer 1

For your example, you could do the following using the cellfun function:

fcnList = {@(x) (x+1), @(x) (x+2)};
a = 2;
cellfun(@(func) func(a),fcnList)
ans =

   3   4

Where I have created a handle called func which accepts as input a function from the fcnList variable. Each function is then evaluated for a.

If you need to pass a vector instead of a scalar, for instance b, you will need to set the 'UniformOutput' option to false:

b=[3 4]
fcnList = {@(x) (x+1), @(x) (x+2)};
cellfun(@(func) func(b),fcnList,'UniformOutput',false)
ans =
{
  [1,1] =
     4   5
  [1,2] =
     5   6
}