Avoid for loop in multi-dimensional problem

I am looking to create a 3D matrix the achieves the following:

A(:,:,1)=[0 -2*pi; 2*pi 0]; A(:,:,2)=[0 -4*pi; 4*pi 0];

Ultimately, I am trying to solve , which in this instance will evaluate to 0. But for now, I just want to figure out how to build the matrix .

I have the following code:

l=0:1; q=0:1; p=2*pi*(1:2);

sub = l(:)-q(:).' % gives a 2x2 matrix

sub2 = repmat(sub,[1 1 2]) % repeats the 2x2 matrix to give a 2x2x2 matrix

for p_ = 1:length(p)

A(:,:,p_) = p(p_)*sub2(:,:,p_);

end

I am looking to conduct a multiplation that yields without having to use a for loop. Any suggestions would be appreciated.

Answer 1

[Stephen23]

Some ideas:

format compact
A = cat(3,[0,-2*pi;2*pi,0],[0,-4*pi;4*pi,0]) % use CAT()

A = 
A(:,:,1) =
         0   -6.2832
    6.2832         0
A(:,:,2) =
         0  -12.5664
   12.5664         0

A = pi*cat(3,[0,-2;2,0],[0,-4;-4,0]) % take out the commom PI

A = 
A(:,:,1) =
         0   -6.2832
    6.2832         0
A(:,:,2) =
         0  -12.5664
  -12.5664         0

A = pi*cat(3,2,4).*[0,-1;1,0] % multiply two arrays

A = 
A(:,:,1) =
         0   -6.2832
    6.2832         0
A(:,:,2) =
         0  -12.5664
   12.5664         0

A = cat(3,2,4).*[0,-pi;pi,0] % multiply two arrays

A = 
A(:,:,1) =
         0   -6.2832
    6.2832         0
A(:,:,2) =
         0  -12.5664
   12.5664         0

[Howard Wilton]

thank you sir!