how can i use for loop for this script
3 views (last 30 days)
Show older comments
shoaib Shoaib
on 6 May 2021
Commented: Sambit Supriya Dash
on 6 May 2021
for b=1:1:1200
omega(b)=b;
Omega(b)=omega(b)*2*pi;
alpa=-(roh*omega(b)^2/E)-(roh*omega(b)/k*G);
beta=-(roh*A*omega(b)^2/E*I)-(roh^2*omega(b)^4/E*k*G);
for j=1:4
k_j(b) =(-1)^(j(b)/2)*([sqrt(alpa+(-1)^j(b))*sqrt((alpa)^2+4*beta)/2]);
k1(b)=k_j(b);
k2(b)=k_j(b);
k3(b)=k_j(b);
k4(b)=k_j(b);
5 Comments
DGM
on 6 May 2021
Edited: DGM
on 6 May 2021
I see that there are loops. I asked what j(b) is supposed to be. The variable j is a scalar within the scope of the inner loop. You are trying to find j(1:1200). There is no j(2), let alone j(1200). I don't understand what you're trying to do with this expression.
Also: is Omega different than omega, or is that a typo?
This doesn't appear to need any loops. Just use two orthogonal vectors, and your results will be 1200x4
b = (1:1200).';
roh = 0.1;
A = 1;
E = 1;
k = 1;
G = 1;
I = 1;
omega = 2*pi*b; % i'll assume that Omega is a typo
alpa = -(roh*omega.^2/E)-(roh*omega/k*G);
beta = -(roh*A*omega.^2/E*I)-(roh^2*omega.^4/E*k*G);
j=1:4;
% this whole expression makes no sense
%k_j =(-1)^(j(b)/2)*([sqrt(alpa+(-1)^j(b))*sqrt((alpa)^2+4*beta)/2]);
% if we assume j(b) can be replaced with j
k_j = (-1).^(j/2) .* sqrt(alpa + (-1).^j) .* sqrt(alpa.^2 + 4*beta)/2;
% i guess these are just placeholders?
k1=k_j;
k2=k_j;
k3=k_j;
k4=k_j;
Accepted Answer
Sambit Supriya Dash
on 6 May 2021
As per your given expression in the question,
the assumptions of the constants here taken as 1,
The running code is,
roh = 1; A = 1; E = 1; I = 1; k = 1; G = 1;
for b = 1:1200
omega(b) = b;
Omega(b) = omega(b)*2*pi;
alpa(b) = -(roh*omega(b)^2/E)-(roh*omega(b)/k*G);
beta(b) = -(roh*A*omega(b)^2/E*I)-(roh^2*omega(b)^4/E*k*G);
for j = 1:4
k_j =(-1)^(j/2)*((sqrt(alpa(b)+(-1)^j)*sqrt((alpa(b))^2+4*beta(b))/2));
k1(b)=k_j;
k2(b)=k_j;
k3(b)=k_j;
k4(b)=k_j;
end
end
And the symbolic solution would be,
syms roh A E I k G
for b = 1:1200
omega(b) = b;
Omega(b) = omega(b)*2*pi;
alpa(b) = -(roh*omega(b)^2/E)-(roh*omega(b)/k*G);
beta(b) = -(roh*A*omega(b)^2/E*I)-(roh^2*omega(b)^4/E*k*G);
for j = 1:4
k_j =(-1)^(j/2)*((sqrt(alpa(b)+(-1)^j)*sqrt((alpa(b))^2+4*beta(b))/2));
k1(b)=k_j;
k2(b)=k_j;
k3(b)=k_j;
k4(b)=k_j;
end
end
Hope this helps....
0 Comments
More Answers (2)
Sambit Supriya Dash
on 6 May 2021
k_j(b) =(-1)^(j(b)/2)*([sqrt(alpa+(-1)^j(b))*sqrt((alpa)^2+4*beta)/2]);
Provide the original formula in a text or written manner (not the typed one). Then, I will guide you further.
Sambit Supriya Dash
on 6 May 2021
According to your given document,
As per this formula,
Your parameters in the code should be,
alpha(b) = -((rho*w^2)/E)-((rho*w^2)/(k*G));
beta(b) = -((rho*A*w^2)/(E*I))-(((rho^2)*w^4)/(E*k*G));
k_j(b) = (-1^(j*0.5))*sqrt(((alpha(b)+((-1^j)*(sqrt(((alpha(b))^2)+(4*beta(b)))))))*0.5);
For Symbolic Calculations,
syms rho A E I k G
for b=1:1200
omega = b;
w = omega*2*pi;
alpha = -((rho*w^2)/E)-((rho*w^2)/(k*G));
beta = -((rho*A*w^2)/(E*I))-(((rho^2)*w^4)/(E*k*G));
for j=1:4
k_j(b) = (-1^(j*0.5))*sqrt(((alpha+...
((-1^j)*(sqrt(((alpha)^2)+(4*beta))))))*0.5);
end
k1=k_j;
k2=k_j;
k3=k_j;
k4=k_j;
end
For specific values of the parameters,
rho = 1; A = 1; E = 1; I = 1; k = 1; G = 1;
for b=1:1200
omega = b;
w = omega*2*pi;
alpha = -((rho*w^2)/E)-((rho*w^2)/(k*G));
beta = -((rho*A*w^2)/(E*I))-(((rho^2)*w^4)/(E*k*G));
for j=1:4
k_j(b) = (-1^(j*0.5))*sqrt(((alpha+...
((-1^j)*(sqrt(((alpha)^2)+(4*beta))))))*0.5);
end
k1=k_j;
k2=k_j;
k3=k_j;
k4=k_j;
end
Hope this works good.
0 Comments
See Also
Categories
Find more on Symbolic Math Toolbox in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!