Create a list within a for loop

I have a for loop, in which I solve a coupled second order system. I'm interested in making 2 lists of some values I get from solving this system, but I don't know how to create these lists. I want these list so I can plot them. The values I want is some of the end values from my phase 2, look at the end of the code to see what values I mean.

The code is:

for L = 0.5:0.1:1.5
global L_4 m M M_K L_1 L_2 L_3 theta_i

% constant that varies from experiment to experiment
L_4 = L; %length in meter

% constants
m = 0.006;    %weight in kg
M = 0.640;    %weight in kg
M_K = 0.088;  %weight in kg
L_1 = 0.295;  %length in meter
L_2 = 0.07;   %length in meter
L_3 = 0.0925; %length in meter
theta_i = 48*(pi/180); %angle in radians

% Phase 1
t1 = [0 1.3902]; %reduced time scale
I_1 = [theta_i; 0; 0; 0]; %initial theta, theta', spi and spi'
options = odeset('RelTol',1e-9,'AbsTol',1e-9,'Events',@Begivenheder_fase1);
[T1,Y1] = ode45(@DifLign_fase1,t1,I_1,options);  %call of ode45 to solve the system

L   = L_3/L_2;
l   = L_1/L_2;
l_4 = L_4/L_1;
b1  = theta_i;
mu  = m/M;
mu_b= M_K/M;

sin_phi =   (cos(b1)-cos(Y1(:,1)))/l_4;
phi     =   asin(sin_phi);   
cos_phi =   cos(phi);
f       =   -cos(Y1(:,1)-phi)./cos_phi;
df      =   sin(Y1(:,1)-phi)./cos_phi-sin(Y1(:,1)).^2/l_4./cos_phi.^3;

HS1  = (1-1/2*mu_b*(l-1))*sin(Y1(:,1))+L*sin(Y1(:,1)+Y1(:,2)).*Y1(:,4).^2-mu*l^2*f.*df.*Y1(:,3).^2;
HS2  = -sin(Y1(:,2))+sin(Y1(:,1)+Y1(:,2)).*Y1(:,3).^2;

VS11 = 1+mu*l^2*f.^2+1/3*mu_b*(l^2-l+1);
VS12 = L*cos(Y1(:,1)+Y1(:,2));
VS21 = cos(Y1(:,1)+Y1(:,2));
VS22 = L*ones(size(VS11,1),1);
L_off       = ones(size(VS11,1),1);
NormalForce = ones(size(VS11,1),1);
for i=1:size(VS11,1)
  VS   = [VS11(i) VS12(i); VS21(i) VS22(i)];
  HS   = [HS1(i);HS2(i)];
  Angular_acc = inv(VS)*HS;
  acc = Angular_acc(1);
  L_off(i)=cos(phi(i)-Y1(i,1))*acc;
  L_off(i)=L_off(i)+sin(phi(i)-Y1(i,1))*Y1(i,3)^2+sin(Y1(i,1))^2*Y1(i,3)^2/l_4/cos_phi(i)^2;
  L_off(i)=l*sin_phi(i)*L_off(i);
  L_off(i)=L_off(i)-cos_phi(i)^2;
  NormalForce(i) = -m*1000*L_off(i);
end

% Phase 2
% initial values
Y_1 = Y1(:,1); % Extract first column
Y_2 = Y1(:,2); % Extract second column
Y_3 = Y1(:,3); % Extract third column
Y_4 = Y1(:,4); % Extract last column
phi = asin(L_1/L_4*(cos(theta_i)-cos(Y_1(end)))); %phi start value
t2 = [T1(end) T1(end)+0.8]; %reduceret time scale
I_2 = [Y_1(end); Y_1(end); phi; Y_1(end); Y_1(end); 0]; %initial values
[T2,Y2] = ode45(@DifLign_fase2,t2,I_2);  %call of ode45 to solve the system

% List of release angle theta and phi
Y2_1 = Y2(:,1); % Extract first column (theta)
Y2_3 = Y2(:,3); % Extract second column (phi)
theta = Y2_1(end); %Creating a list of the release angles theta
phi = Y2_3(end);   %Creating a list of the release angles phi

end

[Star Strider]

What do you mean by ‘list’?

[Mufas]

Oh, I want something like this

[value1; value2; value3; .....]

[Star Strider]

It seems to me you can do that essentially as you wrote it. All you have to do is assign it to a variable:

List1 = [value1; value2; value3; .....];

What problems are you having doing that sort of vertical concatenation?

[Mufas]

My problem is that the value, lets say value1 should be the the last value of the array my ode45 gets in the first loop, and value2 should be the last value of the array my ode45 gets in the second loop, and so on. I don't know how to do that. Hope it's understandable.

Answer 1

[Star Strider]

Since ‘Y2’ has 3 columns, you can create list by first preallocating it, then saving it:

Y2_final = nan(size(VS11,1), 3);                            % Preallocate
for i=1:size(VS11,1)
    . . . CODE . . .
    [T2,Y2] = ode45(@DifLign_fase2,t2,I_2);  %call of ode45 to solve the system
    . . . CODE . . .
    Y2_final(i,:) = Y2(end,:);                              % Save Last Value Of Each ‘Y2’
end

If you want to include the times as well, the code becomes:

T2Y2_final = nan(size(VS11,1), 4);                          % Preallocate
for i=1:size(VS11,1)
    . . . CODE . . .
    [T2,Y2] = ode45(@DifLign_fase2,t2,I_2);  %call of ode45 to solve the system
    . . . CODE . . .
    T2Y2_final(i,:) = [T2(end) Y2(end,:)];                  % Save Last Value Of Each ‘T2’ & ‘Y2’
end

This is UNTESTED CODE but should work.