Nested Structure in cellfun

I have a structure that store lots of variable. I want to find function value of these x values. But there is wrong result. My variables :

StartingValue.x ={};
StartingValue.fn =[];

My function is

f = @(x) sin(5.1*pi.*x+0.5).^6;

I created a nested structure and i want to function value of this variable.

StartingValue(1).Next(1).x 
= Columns 1 through 6

      [0.0025]    [0.0075]    [0.0125]    [0.0175]    [0.0225]    [0.0275]

    Columns 7 through 10

      [0.0325]    [0.0375]    [0.0425]    [0.0475]

To find function values i wrote this code:

StartingValue(1).Next(1).fn=cellfun(f,StartingValue(1).Next(1).x)

ans =

    Columns 1 through 8

      0.0185    0.0385    0.0716    0.1213    0.1899    0.2781    0.3838    0.5023

    Columns 9 through 10

      0.6263    0.7464

This result is not correct according to mathematical calculation. I couldn't find what mistake i did. I used cellfun because of x variable is a cell array. I didn't understand whether problem is nested structure or cellfun. If my question is not clear, i can post all code.

Answer 1

[Guillaume]

The result is entirely correct. Perhaps you're assuming that sin works in degrees? If that is the case, use sind instead of sin.

By the way, there is no reason to use a cell array for your example, a vector would make the code a lot simpler:

StartingValue(1).Next(1).x = [0.0025, 0.0075, 0.0125, 0.0175, 0.0225, 0.0275, 0.0325, 0.0375, 0.0425, 0.0475]
f = @(x) sin(5.1*pi.*x+0.5).^6;
StartingValue(1).Next(1).fn = f(StartingValue(1).Next(1).x)

Also note that the fn field name is misleading since its content is not a function but a vector.

[Ozge Moral]

I need to use cell arrays because i will concatenate arrays in another part of code. First part of my code is

f = @(x) sin(5.1*pi.*x+0.5).^6;
StartingValue = initialization(0,1,20);
StartingValue.fn = cellfun(f,StartingValue.x);

When i works as only StartingValue.fn with same x values above, results :

ans =

    Columns 1 through 8

      0.2316    0.9498    0.0449    0.0000    0.3065    0.8929    0.0261    0.0001

    Columns 9 through 16

      0.3916    0.8190

But after i created nested structure StartingValue.Next, and run it for same x values, results(my original question results i mean ) was different above.Therefore i thought results are not correct.

[Guillaume]

Not knowing what initialization does, it's difficult to diagnose the problem, but applying f to 0.0025 should result in ~0.01848, not ~0.2316.

[Ozge Moral]

function [ StartingValue] = initialization( a,b,n )

% [a,b] is interval of function that minimum points will search.
% n is pre-assigned number, # of subinterval.
% Intervals and midpoint of these intervals are described.
% a=a;
% b=b;
% n=n;
sz=(b-a)/n;
StartingValue.interval = {};
StartingValue.x ={};
StartingValue.fn =[];
StartingValue.eta =[];
StartingValue.allowed = [];
StartingValue.Ants = ones(n,1);

for i=1:n
    StartingValue.interval{i} = [a+(i-1)*sz a+i*sz];
    StartingValue.x{i} = a+(i-0.5)*sz;
end

end

It describes initial values only. I couldn't find why result is wrong. Thank you a lot for interesting.

[Guillaume]

There's a factor of 10 difference between the values generated by your initialization function, and the values in your original post:

0.025 vs 0.0025

This explains the vastly different results.

[Ozge Moral]

i'm going to show my eyes to doctor! Thanks a lot.