error in function b=2*pi*ones(n,1);

Hi guys, I create this function to solve a manual shear type chase on Matlab:

function[T,Mpar,Mfinale,autovettori,autovalori] = telaio(M,K) C=M\K; [autovettori,autovalori]=eig(C); a=diag(autovalori); omega=a.^0.5; b=2*pi*ones(4,1); T=b./omega; Mstar=autovettori'*M*autovettori; Num=autovettori'*M*ones(4,1); gamma=Num'/Mstar; MSTAR=diag(Mstar)'; Mpar=(gamma.^2).*MSTAR; [Mtot]=sum(Mpar); Mfinale=ones(4,1); for i=4:-1:1 Mfinale(i)=Mpar(i)/Mtot*100; end

when I write in the EDU>> telaio(M,K) (with M and K just defined in the work space) I have this error: Error in telaio (line 6) b=2*pi*ones(n,1);

anybody can help me?! Please!

Thanks a lot!

Answer 1

[Star Strider]

I can’t reproduce your error. I don’t know what ‘M’ and ‘K’ are supposed to be, but

M = 7;
K = 5;
[T,Mpar,Mfinale,autovettori,autovalori] = telaio(M,K)

runs without error.

I noticed however, that the code you attached is not the code you apparently ran that threw the error. Line #6 in your code is:

b=2*pi*ones(4,1);

but the error is in this line:

b=2*pi*ones(n,1);

with ‘n’ undefined.

See if changing your function declaration statement to:

function[T,Mpar,Mfinale,autovettori,autovalori] = telaio(M,K,n)

to pass ‘n’ as a parameter, or define ‘n’ from the size of your matrices.

[Star Strider]

Nicola’s Answer moved here:

Hi Thank you very much, I made a mistake the correct function is:

function[T,Mpar,Mfinale,autovettori,autovalori] = telaio(M,K) C=M\K; [autovettori,autovalori]=eig(C); a=diag(autovalori); omega=a.^0.5; b=2*pi*ones(n,1); T=b./omega; Mstar=autovettori'*M*autovettori; Num=autovettori'*M*ones(n,1); gamma=Num'/Mstar; MSTAR=diag(Mstar)'; Mpar=(gamma.^2).*MSTAR; [Mtot]=sum(Mpar); Mfinale=ones(n,1); for i=n:-1:1 Mfinale(i)=Mpar(i)/Mtot*100; end

I have two matrix for M and K in the workspace, they are two 4x4 matrix.

Do you need the matrix? you should insert number you won't, I desire only to eliminate the error below.

Thanks a lot!

[Star Strider]

My pleasure!

See if this does what you want:

function[T,Mpar,Mfinale,autovettori,autovalori] = telaio(M,K)
C=M\K;
[autovettori,autovalori]=eig(C); 
n = size(M,1);
a=diag(autovalori); 
omega=a.^0.5;
b=2*pi*ones(n,1); 
T=b./omega; Mstar=autovettori'*M*autovettori; 
Num=autovettori'*M*ones(n,1); 
gamma=Num'/Mstar; 
MSTAR=diag(Mstar)'; 
Mpar=(gamma.^2).*MSTAR; 
[Mtot]=sum(Mpar); 
Mfinale=ones(n,1); 
for i=n:-1:1 
    Mfinale(i)=Mpar(i)/Mtot*100; 
end

[Nicola Violetti]

Hi Star, thanx a lot! I have correct results for T (periods) and Mfinale (i)… but I have incorrect results for Autovettori… Have ou idea? Very thanks!

[Star Strider]

My pleasure!

I honestly do not have any idea what the problem is with your code. I have no idea what you are doing.