eigen value is not showing

k0=2*pi/l;
nc=1.33;
ec=nc^2;
na=1.43;
ea=na^2;
nf=1.59;
ef=nf^2;
nm=0.064+1i*4;
em=nm^2;
ns=1.495;
es=ns^2;
df=0.5e-6;
dm=0.03e-6;
da=0.06e-6;




kc=sqrt(kx.^2-ec*k0^2);
ka=sqrt(ea*k0^2-kx.^2);
kf=sqrt(ef*k0^2-kx.^2);
km=sqrt(em*k0^2-kx.^2);
ks=sqrt(kx.^2-es*k0^2);


a11=exp(-ks*dm);
a12=-exp(-km*dm);
a13=exp(km*dm);
a14=0;a15=0;a16=0;a17=0;a18=0;
a21= ks.*exp(-ks*dm);
a22=1i*km.*exp(-1i*km*dm);
a23= -1i*km.*exp(1i*km*dm);
a24=0;
a25=0;a26=0;a27=0;a28=0;
a31=0;a32=1;a33=1;a34=-1;a35=-1;a36=0;a37=0;a38=0;
a42=1i*km;a41=0;a43=-1i*km;a44=-1i*kf;a45=1i*kf;a46=0;a47=0;a48=0;
a51=0;a52=0;a53=0;a54=exp(1i*kf*df); a55=exp(-1i*kf*df);a56=-exp(1i*ka*df);a57=-exp(-1i*ka*df);
a58=0;a61=0;a62=0;a63=0;a64=1i*kf.*exp(1i*kf*df);a65=-1i*kf.*exp(-1i*kf*df);
a66=-1i*ka.*exp(1i*ka*df);a67=1i*ka.*exp(-1i*ka*df);a68=0;
a71=0;a72=0;a73=0;a74=0;a75=0;a76=exp(1i*ka*(da+df));
a77=- exp(-1i*ka*(da+df));a78= exp(-1i*kc*(da+df));
a81=0;a82=0;a83=0;a84=0;a85=0;a86=1i*ka.* exp(1i*ka*(da+df));a87=-1i*ka.*exp(-1i*ka*(da+df));
a88=kc.*exp(1i*kc*(da+df));





Phi=[a11  a12  a13  a14  a15  a16   a17  a18; a21  a22  a23  a24  a25  a26   a27  a28; a31  a32  a33  a34  a35  a36   a37  a38; a41  a42  a43  a44  a45  a46   a47  a48; a51  a52  a53  a54  a55  a56   a57  a58; a61  a62  a63  a64  a65  a66   a67  a68; a71  a72  a73  a74  a75  a76   a77  a78; a81  a82  a83  a84  a85  a86   a87  a88];

eig(Phi)

[shiv gaur]

l=0.6328*10^-10 value of eigen value

[KSSV]

Is the code working in the first place?

[shiv gaur]

not working till now

[KSSV]

Then specify the error you have and the problem you are facing with the code. The ocde given lot of variables are not defined.

[Steven Lord]

What does "not working" mean in this context?

• Do you receive warning and/or error messages? If so the full and exact text of those messages (all the text displayed in orange and/or red in the Command Window) may be useful in determining what's going on and how to avoid the warning and/or error.
• Does it do something different than what you expected? If so, what did it do and what did you expect it to do?
• Did MATLAB crash? If so please send the crash log file (with a description of what you were running or doing in MATLAB when the crash occured) to Technical Support using the Contact Support link on the Support section of the MathWorks website so we can investigate.

[shiv gaur]

only kx variable is to be root of the equation all the parameter as mention

[KSSV]

The very first line:

k0=2*pi/l;

Unrecognized function or variable 'l'.

[shiv gaur]

l=0.6328*10^-10;

[VIGNESH B S]

What is this code for ?

[shiv gaur]

to calculate the value of eigen value

[John D'Errico]

k0=2*pi/l;

Your variable l is undefined. There may be other problems with your code of course. But we can go no further than that.

[shiv gaur]

the l value is 0.6328*10^-10

[John D'Errico]

It is a REALLY, REALLY, REALLY bad idea to define a variable named lower case L, so l. That is because l and the number 1 look almost indistinguishable in some fonts. O and 0 are another case that you really need to avoid.

Next, learn to use scientific notation.

l = 0.6328e-10

Next, when I try to execute your code, I see this error:

'kx' requires Datafeed Toolbox. 

That is because you never defined the variable kx, but then you have these lines:

kc=sqrt(kx.^2-ec*k0^2);
ka=sqrt(ea*k0^2-kx.^2);
kf=sqrt(ef*k0^2-kx.^2);
km=sqrt(em*k0^2-kx.^2);
ks=sqrt(kx.^2-es*k0^2);

I still cannot get to the end of your code to know what is happening. As I read through all of your comments, it appears that you want kx to be an unknown?

If so, then eig CANNOT work, because the result will be a symbolic matrix with an unknown variable in it. And that must fail, because the matrix is of size 8. I you remember that the eigenvalues of a matrix can be considered as the roots of a characteristic polynomial of that matrix. Since the polynomial will be of degree at least 8, tthen eig will fail.