splitting a matlab matrix into several equal parts

Question

I have a matrix of size 64500x17. It represents detected texton features that I have to use to find 5 centroids for kmeans.

What I need is:

Answer 1

Just use indexing and store the extracted matrices in cells for easier handling:

data = rand(64500,17);
Nsubsets = 5;
Nsubsize = size(data,1)/Nsubsets;

splitted_data = cell(Nsubsets ,1);
splitted_data_means = cell(Nsubsets,1);

for ii=1:Nsubsets 
    splitted_data{ii} = data((ii-1)*Nsubsize + (1:Nsubsize),:);
    splitted_data_means{ii} = mean(splitted_data{ii});
end

you can then join these means with:

joined_means = cell2mat(splitted_data_means);

Or just for the heck-of-it with the one-liner:

joined_means = cell2mat(arrayfun(@(ii) mean(data((ii-1)*12900+(1:12900),:)),(1:5)','uni',false));

which would be even simpler with @angainor's mat2cell:

joined_means = cell2mat(cellfun(@mean,mat2cell(data, 12900*ones(5,1), 17),'uni',false));