Including codes in a for loop that would store values after each iteration

Hello everyone, I am fairly new to matlab so please bear with me although its a fairly fundemental for loop question. The simulink model you see above simulates two robots that try to form a formation thus they exchange their position informations (p1,p2). They robot 1 does its calculations in "compute_u1" where it outputs an updated p1 value, similar with robot 2. Both position vectors p1 and p2 are in the form of [x-coordinate y-coordinate] therefore their sizes are (1x2). Yet since a simulation is ran with a stop time of 40 and a step time of 0.01 the final sizes of each vectors becomes a (4001x2) so, p1-->(4001x2) similarly p2-->(4001x2).

Now I have this for loop:

for n = 1:sample
    
    thisfig = figure();
    
    p1_0 = rand(2,1)*10-5;    
    p2_0 = rand(2,1)*10-5;     
    
    simOut = sim('hetero1d1b');
    
    alldata = simOut.ScopeDataHetero1d1b;
    time = alldata.time;
    data = alldata.signals;
    
    p1 = data(1).values;
    p2 = data(2).values;
    
    x1_total(:,n) = p1(:,1);
    y1_total(:,n) = p1(:,2);
    x2_total(:,n) = p2(:,1);
    y2_total(:,n) = p2(:,2);
    
end;

basically I ran the simulink model simulation, import the data obtained from it and split the p1 and p2 values into x1,y1,x2,y2 values. But since I have (:,n) on them each variable stores its values after each iteration so if I ran the simulink model with sample=3 I would get x1_total with a size (4001x3).

My problem:

There are serious of calculations which I want to calculate per iteration and I want to be able to store all the values of these calculations so that I can average them out after simulating my models for sample= 3. These calculations are as follows:

alphad2 = 240; %constant value that doesnt get updated
desireddistance = sqrt((p2(:,1)-p1(:,1)).^2+(p2(:,2)-p1(:,2)).^2);
g12 = (p2(:,:)-p1(:,:))./desireddistance;
g12_star = [cosd(alphad2) sind(alphad2)]; %constant value that doesnt get updated
G12_star = ones(4001,2).* g12_star;       %constant value that doesnt get updated
e12b = g12-G12_star
e12bnorm = sqrt(sum(e12b.^2,2))

How can I encorporate these equations in my for loop so that if I ran my simulation for example for n=3 I would have "desireddistance", "g12", "e12b" and "e12bnorm" values store their values per each iteration??? I tried many different versions but either I get a size error or some other error...

I know it's a pretty long one but it's a pretty important matter to me at the moment and I didn't want anyone to have misunderstandings while reading it!

Answer 1

[Ishank Agarwal]

Try this:

sample = input('Enter the number of times you want to run the simulation: ');

g12 = zeros(sample, 1); % preallocation of memory as per sample size

e12b = zeros(sample, 1); % preallocation of memory as per sample size

e12bnorm = zeros(sample, 1); % preallocation of memory as per sample size

alphad2 = 240; %constant value that doesnt get updated

g12_star = [cosd(alphad2) sind(alphad2)]; %constant value that doesnt get updated

G12_star = ones(4001,2).* g12_star; %constant value that doesnt get updated

desireddistance = sqrt((p2(:,1)-p1(:,1)).^2+(p2(:,2)-p1(:,2)).^2);

for i = 1:sample

g12(i, 1) = (p2(:,:)-p1(:,:))./desireddistance;

e12b(i, 1) = g12-G12_star

e12bnorm(i, 1) = sqrt(sum(e12b.^2,2))

end

Thanks