Outputs into a vector

Hello. I want to put the outputs for every loop into a vector form that contains all the values that the loop gives for L_max and D_max for every loop trial. Please help!

% Defining Scenario Independent Paramters: 
%For Rocket
%Payload mass:
M_L=1;%kg 
%Number of fins:
N=3; 
%Shell density:
rho_s=2700; %kg/m^3 
%Propellant density:
rho_p=1772; %kg/m^3 
%Shell working stress:
sig_s=60*10^6; %pa 
%Gravity: 
g=9.81; % m/s^2
 
%For air: 
%Atmorspheric TeM_perature at sea level: 
T_atm=298;
%Specific heat ratio of air:
gamma=1.4; 
%Density of air at sea level: 
rho=1.225; 
%Pressure at sea level:
P_a=101325; %pa 
 
%% Scenario 1: h_max = 20000 ft , a_max = 10 m/s^2, SM = 1: Iteration
 
%Maximum Altitude
%h_max= 0.3048*[20000 20000 20000 2000 2000 10000 30000 10000 30000]; %m
%a_max= [10 10 10 5 20 10 10 5 20]
%SM = [1 2 3 2 2 2 2 1 3]

Data=readmatrix('Data');% Each col is 1 test
D_max=zeros(1,9);
L_max=zeros(1,9);
for i=1:9;
    h_max=Data(1,i);
    a_max=Data(2,i);
    SM=Data(3,i);
    R_max=1+a_max;
    W_eq=sqrt((h_max*g)/(((log(R_max)/2)*(log(R_max)-2))+((R_max-1)/R_max)));
    t_bmax=(R_max-1)*W_eq/(g*R_max);
    M_eq=W_eq/sqrt(gamma*287*T_atm);
    P_c=P_a*(1+(((gamma-1)/2)*M_eq^2))^(gamma/(gamma-1));
    P_0_a=P_c/P_a;
     
    %% Scenario 1 Iteration for best L, D
    % Creating Length and Diameter Limiatation for Iteration  
    L=linspace(0.0001,4,5000); %m 
    D=linspace(0.0001,2,5000); %m 
     
    %%Iteration through all the parameters: 
    for i=1:length(D);
        for j=1:length(L)
            delta= (P_c/(2*sig_s))*D(i); % thickness of shell m
            M_n=delta*rho_s*pi*D(i)*(D(i)+sqrt(D(i)^2+(D(i)^2/4)));
            M_f=((D(i)^2)/2)*delta*rho_s;
            M_f_b=(pi*D(i)*rho_s*D(i)*delta);
            M_s=(pi*D(i)*rho_s*L(j)*delta)+M_n+M_f+M_f_b;%%%%%%%%%%
            M_p=(R_max-1)*(M_s+M_L);
            L_p=(M_p/(pi*D(i)^2*rho_p/4));
            if L_p<L(j)+D(i)
                % Center of Pressure for Rocket Nose
                X_n=(2/3)*D(i);%m
                CN_n=2;
                 
                %Center of Pressure for Rocket Fin
                a=D(i);%m
                s=D(i);%m
                b=0;
                m=a-b;
                fin_hyp=sqrt(2)*D(i);%m
                X_f=D(i)+L(j);%m
                delta_X_f=((m*(a+2*b))/(3*(a+b)))+((1/6)*(a+b-((a*b)/(a+b))));%m
                X_f_dash=X_f+delta_X_f;%m
                CN_f=(4*N*(s/D(i))^2)/(1+sqrt(1+((2*fin_hyp)/(a+b))^2));%m
                k_fb=1+((D(i)/2)/(s+(D(i)/2)));%m
                CN_fb=k_fb*CN_f; %m;
                X_cp=((CN_n*X_n)+(CN_fb*X_f_dash))/(CN_n+CN_fb);
                 
                 
                %Center of Gravity for Rocket Cone:
                X_ncg=2*D(i)/3;
                M_n=delta*rho_s*pi*D(i)*(D(i)+sqrt(D(i)^2+(D(i)^2/4)));
                M_c=M_L+M_n;
                %Center of Gravity for Rocket Fin
                X_f_cg=(2*D(i)/3)+L(j)+D(i);
                M_f=((D(i)^2)/2)*delta*rho_s;
                %Center of Gravity for Rocket Tube 1
                L_1=L(j)+D(i)-L_p;
                xL_1_cg=(L_1/2)+D(i);
                M_L_1=pi*D(i)*L_1*delta*rho_s;
                %Center of Gravity for Rocket Tube 2
                L_2=L_p;
                xL_2_cg=(L_2/2)+D(i)+L_1;
                M_L_2=(pi*D(i)*L_2*delta*rho_s)+M_p;
                X_cg=((M_c*X_ncg)+(M_L_1*xL_1_cg)+(xL_2_cg*M_L_2)+(X_f_cg*M_f*3))/(M_c+M_L_1+M_L_2+(M_f*3));
                 
                cond(i,j)=X_cp-X_cg-(D(i)*SM);
                if cond(i,j)<0 || cond(i,j)>0.00001
                   continue
                end   
                L_D(i,j)=L(j)/D(i);
                lamda(i,j)=M_L/(M_s+M_p);
            else
                continue
            end
        end
 
    end
     
    %% Scenario 1 Output 
    % Matrix indexing for the D_max and L_max
    [M,I] = max(lamda,[],'all','linear');
    [row,col] = ind2sub(size(lamda),I);
    D_max=D(row)
    L_max=L(col)

end

Answer 1

[Geoff Hayes]

Mohsen - you've already declared D_max and L_max as arrays with

D_max=zeros(1,9);
L_max=zeros(1,9);

so all you need to do is access the correct element on each iteration of the loop

    %% Scenario 1 Output 
    % Matrix indexing for the D_max and L_max
    [M,I] = max(lamda,[],'all','linear');
    [row,col] = ind2sub(size(lamda),I);
    D_max(i)=D(row)
    L_max(i)=L(col)

The above is valid only if D(row) and L(col) are scalars. Is this the case?

[Mohsen Nashel]

Yes they are scalars. The adjustment you suggested returned a large array of zeros with the value at the end. What I need is a vector that contains all values returned from the loop.

[Geoff Hayes]

Are you sure that they are scalars? What are the dimensions of D_max and L_max once the code has completed? Remember, I can't run your code without the

Data=readmatrix('Data');% Each col is 1 test

One thing that you may want to reconsider is using i as your step variable for two of your for loops

for i=1:9;
 
    % some code
    
    %%Iteration through all the parameters: 
    for i=1:length(D);