CODEWITHSUNDEEP
matlab
Galal
Galal

Reputation: 41

Summation of cell array of function handles

I have a cell array with size (n,1) that includes a function handle. Every cell has to include specific function handle and the summation of function handles in the previous cells. How can I perform this operation? To clarify this is an illustration.

A = cell(size(ones(n,1)));
for i = 1 : n
    A{i,1} = @(x) A{i-1,1} + i .* x;
end

How to get A{n,1} at x = 2 (for example)

Upvotes: 2

Views: 268

Answers (2)

EBH
EBH

Reputation: 10450

Recalling @gnovice comment, you can also just make a cell array of the handles, and then call a function that sums them up to n:

N = 10;
A = cell(N,1);
A{1} = @(x) 1.*x;
for k = 2:N
    A{k} = @(x) k.*x;
end

% the following function sums the output of A{1}(x) to A{n}(x):
f = @(n,x) sum(cellfun(@(c) c(x),A(1:n)));

The result:

>> f(5,2)
ans =
    30
>> f(N,2)
ans =
   110

This way, every change of the functions in A will have an immediate effect upon redefining f:

>> A{3} = @(x) -x;
>> f = @(n,x) sum(cellfun(@(c) c(x),A(1:n)));
>> f(N,2)
ans =
   102
>> f(5,2)
ans =
    22

Upvotes: 2

rinkert
rinkert

Reputation: 6863

You are actually pretty close, but you need to add a special case for i = 1 and you need to call the function:

n = 10;
A = cell(size(ones(n,1)));

A{1,1} = @(x) 1 .* x;
for ii = 2 : n
    A{ii,1} = @(x) A{ii-1,1}(x) + ii .* x;
end

I replaced i with ii, to avoid confusion with complex numbers. For the case n = 10:

>> A{n}(2)

ans =

   110

Upvotes: 3

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