function [Z,A,S] = load_data(TYPE,samples, signals, snapshots)
%clc,clear,close all;
%TYPE = "DOA";samples = 10; signals=2; snapshots = 1000;

%==================
% Z = A*S
% Z: output (samples x snapshots)
% A: subspace (samples x signals)
% S: signal  (signals x snapshots)

%==================
if TYPE == "random"
    A = rand(samples, signals);
    S = rand(signals,snapshots);
    Z = A*S;
elseif TYPE == "DOA"
   
    %Initial subspace
    A = {};
    theta1 = 40*pi/180* ones(snapshots,1)+0.2;
    theta2 = (((1:snapshots)/snapshots*20+20)*pi/180)'-0.2;
    theta3 = [10*pi/180*ones(int32(snapshots/3),1); 20*pi/180*ones(int32(snapshots-snapshots/3),1)]-0.3;
    theta4 = [10*pi/180*ones(int32(snapshots/3),1); 10*pi/180*ones(int32(snapshots-snapshots/3),1)]-0.6;
    theta = [theta1,theta2,theta3,theta4];
    if signals < 5 
        theta = theta(:,1:signals);
    else
        disp("Initial more signals");
    end
    
    %doa
    lamda = 1; d = lamda/2;
    f = d/lamda*sin(theta);
    
     for i=1:snapshots
        w = 2*pi*d/lamda .*sin(theta(i,:));
        A{i} = (exp(j.*(0:samples-1)'*w));           
     end
    
    %Initial signal
    S = rand(signals,snapshots);
    
    %Initial observed signal
    Z = zeros(samples,snapshots);
    for ii=1:snapshots
        Z(:,ii) = A{ii}*S(:,ii);   
    end
    
    %show doa
%     figure;
%     plot(f)
end