How can I create a loop and plot a graph after each loop?

Hello everyone,

I have two questions to do with the same code. So I am going to breakdown the questions below:

1. How can I create a for loop that uses a value of beta in each loop?
2. As q is a matrix (2 by 1), how can I plot the values of q1 and q2 separately, each against omega_n? (Also note that omega_n changes after each loop as beta changes)

NB: Just assume any values for the matrices below.

beta = 1:1:4;       % Array of beta values
w = 0:50E3:300E3;
omega = w.*2.*pi./60;       % Array of omega values
omega_n = 3*beta;           % Omega_n is dependant on beta
M = [M_11 0; 0 M_22];       % Matrix M
C = [C_11 C_12; C_21 C_22];     % Matrix C   
K = [K_11 K_12; K_21 K_22];     % Matrix K    
F = [F_1; F_2];                 % Matrix F     
Z = -(omega.^2).*M + omega.*1i.*C + K;  % Matrix Z 
Z_inverse = inv(Z);             % Inverse of Matrix Z   
q = Z\F;                        % Matrix q   

Thanks in advance!

Answer 1

[KALYAN ACHARJYA]

w = 0:50E3:300E3;
omega = w.*2.*pi./60;       % Array of omega values
for beta=1:1:4
omega_n = 3*beta;           % Omega_n is dependant on beta
M = [M_11 0; 0 M_22];          % Matrix M
C = [C_11 C_12; C_21 C_22];     % Matrix C   
K = [K_11 K_12; K_21 K_22];     % Matrix K    
F = [F_1; F_2];                 % Matrix F     
Z = -(omega.^2).*M + omega.*1i.*C + K;  % Matrix Z 
Z_inverse = inv(Z);             % Inverse of Matrix Z   
q= Z\F;                   % Matrix q 
end

For second question clarification needed?

M_11..? M_22...

In each iteration omega_n is scalar (having single value),

Let suppose for first iteration beta=1, therefore omega_n=3

Lets consider q=[2

1] as you mentioned q is 2x1

Now can you elaborate how to do plot between omega_n vs q, I am asking Maths?

[Zeyad Elsayed]

w = 0:50E3:300E3;
omega = w.*2.*pi./60;       % Array of omega values
M_22 = omega./4
C_22 = omega./3
for beta = (2 15 6 8)
omega_n = 3*beta;           % Omega_n is dependant on beta
M = [1 0; 0 M_22];        % Matrix M
C = [1 2; -2 C_22];       % Matrix C
K = [100 0; 0 100];       % Matrix K
F = [200; 36];            % Matrix F 
Z = -(omega.^2).*M + omega.*1i.*C + K;  % Matrix Z 
Z_inverse = inv(Z);             % Inverse of Matrix Z   
q= Z\F;                   % Matrix q 
end

I just realized something else, that some of the values in the Matrix (e.g M_22 and C_22) entries are dependant on omega, meaning that another loop probably needs to be created. So for beta = 1st number, each omega needs to be considered at a time in the matrix itself, then the values of q get stored, then moves to beta = 2nd number.

Clarifying:

So yes for each iteration lets say omega_n=3 and also

lets say q = [2

1], then I want the value to get stored as q1 = 2 and q2 = 1, and two graphs would be created, q1 against omega_n and also q2 against omega_n.

Also note one more thing, treat beta as an array that was solved earlier, eg. beta = (2 15 6 8) - I changed it in the code above.

Thanks Kalyan!

[uzzi]

Kalyan, I want to create a loop such as for loop or while loop for every 6000 rows in table and plot each loop. I can only code for first 6000 rows. I don't know how to repeat it. Can you help me?

https://de.mathworks.com/matlabcentral/answers/1840608-repetitive-looping-and-plotting