Hi Paula Giménez Mínguez,
From the code snippet, what I understand that you are determining if a pixel index matches an uptake index, which is loaded from the "GABA_uptake_points3.mat" file using the SourceY and SourceX variables. By transforming uptake_indices into a logical array, you can efficiently identify whether each pixel is an uptake point. This method enables direct indexing, offering a significant improvement in elapsed time over repeatedly using ismember.
Refer to the below code :
tic;
% List of indexes of the 400x400 image
pareja_indice = reshape(1:(400*400), [400, 400]);
% Load indexes corresponding to uptake points in the image
load('GABA_uptake_points3.mat');
uptake_indices = sub2ind([400, 400], SourceY, SourceX);
% Create a logical array to identify uptake points
uptake_mask = false(400, 400);
uptake_mask(uptake_indices) = true;
% Initialize concentration matrix
uptake = 30;
C = zeros(400, 400);
for k = 1:2000000
% Only perform operations on uptake points
C(uptake_mask) = uptake;
% ... other operations
end
toc;
For more information on logical array, refer to this MATLAB documentation: https://www.mathworks.com/help/matlab/ref/logical.html
Hope this helps!!
