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Speed up code:: Code is working but slow..

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Mark Sc
Mark Sc on 25 Feb 2021
Edited: per isakson on 26 Feb 2021
Hi ,
The code is working fine, but it's very slow... any suggestions ?
clearvars;
clc;
C(1:3,1:3,1:3,1:3) = rand(3,3,3,3)
T = [cos(theta) sin(theta) 0;
-sin(theta) cos(theta) 0;
0 0 1];
T_z = T;
tensor_order = ndims(C);
el_n = numel(C);
C_tran = C;
C_tran(:) = 0;
iie = zeros(tensor_order,1); % initialise vector with indices of input tensor element
ioe = zeros(tensor_order,1); % initialise vector with indices of output tensor element
cum_vector = cumprod(3*ones(tensor_order,1))/3;
for i = 1:el_n, % loop over all output elements
ioe = mod(floor((i-1)./cum_vector),3)+1; % calculate indices of current output tensor element
for j = 1:el_n, % loop over all input elements
pmxx = 1; % initialise product of transformation matrices
iie = mod(floor((j-1)./cum_vector),3)+1; % calculate indices of current input tensor element
for k = 1:tensor_order % loop over all dimensions
pmxx = pmxx * T_z( ioe(k), iie(k) );
end
C_tran(i) = C_tran(i) + pmxx * C(j); % add product of transformation matrices and input tensor element to output tensor element
end
end

Answers (1)

per isakson
per isakson on 25 Feb 2021
Edited: per isakson on 25 Feb 2021
  2 Comments
per isakson
per isakson on 26 Feb 2021
"but it's very slow" Do you mean more than one millisecond? What is an acceptable execution time?
"specially converting sum functions into a for loop" The function, sum(), doesn't appear in your code.

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