split a matrix into two matrices according to some rule

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How can I generate two separate matrices, one containing the coordinates of line A and the other of line B?
load matrix
figure
plot3(matrix(:,1),matrix(:,2),matrix(:,3),'k.','Markersize',5);
axis equal
grid off
I wanted to try this way but it does not seem the best way.
% range
xRange = [xmin xmax];
yRange = [ymin ymax];
zRange = [zmin zmax];
% indices of points in the range
idx = matrix(:,1) >= xRange(1) & matrix(:,1) <= xRange(2) & ...
matrix(:,2) >= yRange(1) & matrix(:,2) <= yRange(2) & ...
matrix(:,3) >= zRange(1) & matrix(:,3) <= zRange(2);
select_matrix = [matrix(idx,1), matrix(idx,2), matrix(idx,3)];
  5 Comments
Alberto Acri
Alberto Acri on 12 Feb 2024
Hi Stephen! sorry, I realised I had not installed 'Image Processing Toolbox'!
Alberto Acri
Alberto Acri on 12 Feb 2024
I wanted to know if there is a way to get the subdivision! I don't have any 'rules' at the moment!

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Accepted Answer

Cris LaPierre
Cris LaPierre on 12 Feb 2024
Edited: Cris LaPierre on 12 Feb 2024
I would look into clustering. Here is an attempt that uses dbscan, a spectral clustring algorithm included in the Statistics and Machine Learning Toolbox.
You can learn more about this and other clustering techniques in our Practical Data Science with MATLAB specialization on Coursera. It's free to enroll. Here is a link to the video Introdcution to Clustering Algorithms.
load matrix.mat
% view the raw data
plot3(matrix(:,1),matrix(:,2),matrix(:,3),'k.','Markersize',5);
% use dbscan to identify clusters
idx = dbscan(matrix,1.5,5);
gscatter(matrix(:,1),matrix(:,2),idx)
  1 Comment
Cris LaPierre
Cris LaPierre on 12 Feb 2024
If you know the number of clusters already, use spectralcluster.
load matrix.mat
idx = spectralcluster(matrix,2);
gscatter(matrix(:,1),matrix(:,2),idx)

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