Function for Compliance Matrix

I want to know what I am doing wrong with these codes

function y = Sbar(S,theta)
%Sbar This function returns the transformed reduced
% compliance matrix "Sbar" given the reduced
% compliance matrix S and the orientation
% angle "theta".
% There are two arguments representing S and "theta"
% The size of the matrix is 3 x 3.
% The angle "theta" must be given in degrees.
m = cosd(theta);
n = sind(theta);
T = [m*m, n*n, 2*m*n; n*n, m*m, -2*m*n; -m*n, m*n, m*m-n*n];
Tinv = [m*m, n*n, -2*m*n; n*n, m*m, 2*m*n; m*n, -m*n, m*m-n*n];
y = Tinv*S*T;

S = ReducedCompliance(155, 12.10, 0.248, 4.40)
theta = -90:10:90

 for i = 1:length(theta)
S(:,:,i) = Sbar(S, theta(i))
 end
 
 %The output is
 S =

    0.0826   -0.0016         0
   -0.0016    0.0065         0
         0         0    0.2273


S(:,:,1) =

    0.0826   -0.0016         0
   -0.0016    0.0065         0
         0         0    0.2273


S(:,:,2) =

    0.0193   -0.0122   -0.0712
   -0.0122    0.0909    0.0452
   -0.0356    0.0226    0.2061

Error using  * 
Inputs must be 2-D, or at least one input must be scalar.
To compute elementwise TIMES, use TIMES (.*) instead.

Error in Sbar (line 13)
y = Tinv*S*T;

Answer 1

[KALYAN ACHARJYA]

May be, one way?

y=Tinv*T.*S;

Example:

>> Tinv
Tinv =
    0.1361    0.5499    0.6221
    0.8693    0.1450    0.3510
    0.5797    0.8530    0.5132
>> T
T =
    0.2417    0.1320    0.5752
    0.4039    0.9421    0.0598
    0.0965    0.9561    0.2348
>> whos S
  Name      Size             Bytes  Class     Attributes
  S         3x3x2              144  double              
>> S(:,:,1)
ans =
    0.4018    0.1233    0.4173
    0.0760    0.1839    0.0497
    0.2399    0.2400    0.9027
>> S(:,:,2)
ans =
    0.9448    0.3377    0.1112
    0.4909    0.9001    0.7803
    0.4893    0.3692    0.3897
>> y
y(:,:,1) =
    0.1266    0.1394    0.1073
    0.0230    0.1079    0.0294
    0.1282    0.3289    0.4558
y(:,:,2) =
    0.2976    0.3819    0.0286
    0.1485    0.5282    0.4612
    0.2613    0.5062    0.1968
>> 

[Jide Williams]

Thanks Kalyan I will verify once I get on MATLAB but it looks great to me! Thanks....I did verify but it wasnt working for me, I thank you anyways. Also remember that the whole thing is wraped in a funtion which makes it difficult to write it the way you did.

I just want the function to iterate along the theta array, giving S matrices as outcomes

[Jide Williams]

I checked but it appears its still not working for me.

[KALYAN ACHARJYA]

Can you share following three things? Run the code and type the following one by one in command window as follows, and requested you to share the details

>>whos Tinv
>>whos Tinv
>>whos S

[Jide Williams]

Ok lemme do that now

[KALYAN ACHARJYA]

Because I considered the same sizes random data, its works in my case. I showed the example also

[Jide Williams]

so it returns 3*3*2, thats not what I want, I want it to return 3*3*19, i.e length of Z = -90:10:90.

Thanks

[Jide Williams]

Thanks, but lemme see the code....it is still not working. When you run the function

S1 = Sbar(S, -90), %You will get a 3*3 matrix

%Now I want to run from:
theta = -90:10:90 %degree

S1-S19 = Sbar(S, theta[-90:10:90]); %S is constant
%I should get 19 3*3 matrices

[KALYAN ACHARJYA]

Have you mentioned this "I want it to return 3*3*19" in the original question?

I sepcifically asked for share the followings

>>whos Tinv
>>whos Tinv
>>whos S

Run the code and Type whos Tinv on commnad window, then enter, show the details here

.....do the same for others

[KALYAN ACHARJYA]

In your case

Tinv is 3x3
T is 3x3
S is 3x3x2 

Can you show, how you can get 3*3*19 after doing multiplication from those matrices?

I am asking basic Maths, not Matlab?

[Jide Williams]

Ok hang on I think I am seeing where the mistake is....gimme a second

[Jide Williams]

I HAVE SEEN MY ERROR and I have been able to solve it. Thanks anyways. see code below

function y = Sbar(S,theta)
for iter = 1:length(theta)
%Sbar This function returns the transformed reduced
% compliance matrix "Sbar" given the reduced
% compliance matrix S and the orientation
% angle "theta".
% There are two arguments representing S and "theta"
% The size of the matrix is 3 x 3.
% The angle "theta" must be given in degrees.
m = cosd(theta(iter));
n = sind(theta(iter));
T = [m.*m, n.*n, 2.*m.*n; n.*n, m.*m, -2.*m.*n; -m.*n, m.*n, m.*m-n.*n];
Tinv = [m.*m, n.*n, -2.*m.*n; n.*n, m.*m, 2.*m.*n; m.*n, -m.*n, m.*m-n.*n];
%y = Tinv*S*T;
y(:,:,iter) = Tinv*S*T;
end

[KALYAN ACHARJYA]

Happy to know that the problem has been resolved

Good Wishes!

[Jide Williams]

Thanks alot I appreciate your guidiance sir!