classdef matlab constructor, how does it work?

I have this piece of code and i have no idea to interpret it.

classdef LTSD
    properties
        winsize
        window
        order
        amplitude
        avgnoise
        windownum
        alpha
        speechThr
    end

[sound,rfs] = audioread(fn);
sound = sound(rfs*cs+1:end-rfs*ce,1);
THRESHOLD = -6; % Threshold to update the noise spectrum
ALPHA = 0.54; % update rate (forgotten factor)
NORDER = 6; % order
WINSIZE = 2048; % window size
WINDOW = hamming(WINSIZE,'symmetric'); % hamming window type

ltsd = LTSD(WINSIZE,WINDOW,NORDER,ALPHA,THRESHOLD);
res =  ltsd.compute(sound);

The problem is that the LTSD constructor doesnt have enough arguments. I wonder how default constructor handle this case

Answer 1

[Guillaume]

It's not clear from your post where the class definition ends and where the calling code (obviously in a different file) starts, I assume it's at [sound, rfs] = …

If a class does not have an explicit constructor, a default constructor is indeed generated for it. That constructor always takes no arguments and leaves all properties at their default (so in your case, leaves everything empty).

So, yes, without an explicit constructor that takes at least 5 arguments, the line

ltsd = LTSD(WINSIZE,WINDOW,NORDER,ALPHA,THRESHOLD);

stands no chance of ever succeeding.

[Minh Nguyen]

https://github.com/isrish/VAD-LTSD

The link above is the repo for the code. If you understand the classdef constructor works after looking at the code. please let me know

[Guillaume]

The class does have a constructor, it's in the middle of the methods block (I prefer to have the constructor at the start but there's no requirement that it is other than clarity).

function obj = LTSD(varargin) %winsize,window,order,adap_rate,threshold
    if nargin>3
        obj.speechThr = varargin{5};
        obj.alpha = varargin{4};
    end
    obj.winsize = varargin{1};
    obj.window = varargin{2};
    obj.order = varargin{3};
    obj.amplitude = {};  
end

The constructor accepts a variable number of arguments. Practically, the code fails if you don't pass either 3 or 5 arguments. If you only pass three arguments, then alpha and speechThr property are left empty which means that some sort of filtering won't happen in the method ltsd (I think it's a bad idea to have a method name that only differs from the constructor name by case, but again that's allowed).

You're passing 5 arguments to the constructor so there's no issue.