How can I get the return of a constructed function as an array?

The constructed function is

function [a] = triangle(n)

a=zeros(size(n));

if (n>=0 & n<=pi) % use an if else statement to execuete

a = pi-n;

else

a = 0; %n; % 0 otherwise

end

end

It can be used with integral function very well. But when I input x = -3:0.01:3, the return velue is 0.

>> x = -3:0.01:3;

>> triangle(x)

ans =

0

>>

Answer 1

[Stephen23]

That is not how MATLAB works. Your code defines a matrix of zeros, but then you do nothing with that variable and simply replace that variable with some other data. Your code also does not take into account the requirements for the IF condition to be considered TRUE (read the IF documentation carefully, if you are interested). If you use IF /ELSE for this then you would need to use a loop and indexing, but your code has neither of these.

In any case, the MATLAB approach is not to use IF/ELSE, but to use logical indexing, e.g.:

x = -3:0.01:3;
y = triangle(x)

y = 1×601

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

nonzeros(y)

ans = 301×1

3.1416 3.1316 3.1216 3.1116 3.1016 3.0916 3.0816 3.0716 3.0616 3.0516

function a = triangle(n)
a = zeros(size(n));
x = n>=0 & n<=pi;
a(x) = pi-n(x);
end

Read more:

https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html

https://blogs.mathworks.com/steve/2008/01/28/logical-indexing/

[Thamrongsin Siripongsakul]

Thank you very much. Everything works correctly. I will read the document you suggested.