Matrix multiplication in 4 D

I have two matrices. The x(r,i,t1,t2) and y(t1) matrix. I want to multiply the matrix y in matrix x for all r, i, and t2. I have the following codes and errors. Could you please help me to realize what is the problem.

     R=8;
    I=12;
    T1=11;
    T2=10;
 x=rand(R,I,T,TT);
 y =[99   129   115   128    96    94    98   107   133    99   120];
 for r=1:R
      for i=1:I
           for t2=1:T2                 
                for t1= 1: T1 
                    xnew(r,i,t1,t2)=y(t1).*x(r,i,t1,t2);     
                       end                  
                end
           end
       end
    Error
Undefined function 'y' for input arguments of type 'double'.
Error in test (line 12)
xnew(r,i,t1,t2)=y(t1).*x(r,i,t1,t2);

[Walter Roberson]

Does it literally say class "y" ? What is your y?

 which -all y

[rezi raf]

@Walter, y is a matrix or vector of the variable t1.

For example if T1=4 the y is a 1 by 4 matrix like [20,30,42,15].

However for example x is a 3*5*4*6 matrix when R=3, I=5, T1=4, and T2= 6.

[Walter Roberson]

Please copy and paste the exact error message. Please also show the output of

which -all y

[rezi raf]

@ Walter, I do not know what you mean by the output of which -all y. Could you please explain that? This is the code and exact error:

    R=8;
    I=12;
    T1=11;
    T2=10;

 x=rand(R,I,T,TT);
 y =[99   129   115   128    96    94    98   107   133    99   120];

 for r=1:R
      for i=1:I
           for t2=1:T2                 
                for t1= 1: T1 

                    xnew(r,i,t1,t2)=y(t1).*x(r,i,t1,t2);     
                       end                  
                end
           end
       end

    Error
Undefined function 'y' for input arguments of type 'double'.
Error in test (line 12)
xnew(r,i,t1,t2)=y(t1).*x(r,i,t1,t2);

[Walter Roberson]

That line of code is not at line 12 of what you have posted -- not unless exactly two out of the three blank lines are not actually present in your code.

[Walter Roberson]

After you run your code and get the failure about y, go to the command line and type in

which -all y

and show us the result.

Also please tell us which MATLAB version you are using.

Please also attach your code as a .m file as your code is not the same as you have posted (your posted code does not define T, and the line numbers are not right for what you posted.)

Answer 1

[the cyclist]

If I replace

x=rand(R,I,T,TT);

with

x=rand(R,I,T1,T2);

your code runs to completion for me.