how can i vectorize it?

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pipin
pipin 2023-8-7
评论： pipin 2023-8-8
Ran in:
HELLO, IT TOOK A LITTLE BEFORE I CODED IT CORRECTLY
I hope I haven't made any mistakes
%%how velocize matrix of array
%I BUILD DATA IN THIS EXAMPLE
row=10;
col=8;
profit = rand(row,col)
profit = 10×8
0.3436 0.1311 0.9776 0.6418 0.2922 0.8690 0.4831 0.5124 0.9126 0.7900 0.3755 0.3017 0.7737 0.8073 0.8464 0.5552 0.8071 0.9526 0.2701 0.4222 0.4250 0.9831 0.4610 0.1624 0.1542 0.1770 0.9003 0.6316 0.6100 0.8506 0.0065 0.7861 0.5361 0.1805 0.1426 0.6149 0.7982 0.9206 0.3312 0.0705 0.3135 0.0977 0.6855 0.9359 0.2368 0.2731 0.9951 0.7932 0.1589 0.8174 0.4833 0.2497 0.0689 0.0655 0.7721 0.8835 0.9792 0.7773 0.1901 0.0859 0.6659 0.8166 0.6375 0.5151 0.6811 0.0662 0.0089 0.6860 0.7540 0.0032 0.8470 0.7785 0.8207 0.2034 0.2639 0.4568 0.2538 0.2146 0.0026 0.6747
c3 = randi(size(profit,2),row,col);
maxcat = 3;
fr = ones(size(profit));
group=row-1; %group must to be <row)
c3(rand(group,col)<0.4)=0 % i use this code to turn off some element in c3
c3 = 10×8
2 3 0 0 6 0 6 8 0 8 7 8 4 6 0 4 7 6 3 8 0 5 0 1 0 7 6 2 6 0 1 3 5 1 0 0 0 4 0 4 5 4 0 3 6 0 2 2 0 5 2 0 0 7 0 8 0 0 4 6 0 5 6 8 3 0 0 0 8 0 3 2 1 7 0 2 0 0 0 6
%%*****************************
%*****************************THIS IS CODE TO VELOCIZE
for r=1:row
for x=1:group %(rank group)
z=c3(x,c3(x,:)>0); %find element >0
A=profit(r,z);
[~,idxx]=sort(A,'descend');
idxxx=idxx(maxcat+1:end);
if ~isempty(idxxx)
fr(r,z(idxxx))=0;
end
end
end
% EDIT: View results
fr
fr = 10×8
0 0 1 1 0 1 0 0 1 0 0 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 0 0 1 1 0 0 0 0 1 1 0 0 1 0 0 1 0 0 0 0 1 1 1 0 0 0 0 1 0 0 0 0 0 0 1 0 1 1 1 0 1 0 0 0 0 1

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Bruno Luong
Bruno Luong 2023-8-8
编辑：Bruno Luong 2023-8-8
Ran in:
If you prefer ugly and unreadable code
%I BUILD DATA IN THIS EXAMPLE
row=10;
col=8;
profit = rand(row,col);
c3 = randi(size(profit,2),row,col);
maxcat = 3;
fr = ones(size(profit));
group=row-1; %group must to be <row)
c3(rand(group,col)<0.4)=0; % i use this code to turn off some element in c3
%%*****************************
%*****************************THIS IS CODE TO VELOCIZE
for r=1:row
for x=1:group %(rank group)
z=c3(x,c3(x,:)>0); %find element >0
A=profit(r,z);
[~,idxx]=sort(A,'descend');
idxxx=idxx(maxcat+1:end);
if ~isempty(idxxx)
fr(r,z(idxxx))=0;
end
end
end
% EDIT: View results
fr
fr = 10×8
1 0 1 1 0 0 0 0 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 0 1 0 0
fr = ones(size(profit));
% vectorize method
[~,j,c] = find(c3(1:group,:)');
c = accumarray(j, c, [], @(i){i});
k = max(cellfun(@height, c)-maxcat, 0);
[~, j] = arrayfun(@(c,k)mink(profit(:,c{1}), k, 2), c, k, 'unif', 0);
cj = cellfun(@(c,j) c(j), c, j, 'unif', 0);
fr((1:row)' + row*([cj{:}]-1)) = 0;
fr
fr = 10×8
1 0 1 1 0 0 0 0 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 0 1 0 0
  2 个评论
Mike Croucher
Mike Croucher 2023-8-8
Ran in:
It may be ugly and unreadable but its many times faster! Nice work
I took your code and increased the problem size to give it something more meaty to process: setting
row=1000;
col=8;
give the following times on my machine
origTime =
1.7324
vectorTime =
0.0613
Vectorised method is 28.254690 times faster
Full code for anyone who wants to reproduce this:
%%how velocize matrix of array
%I BUILD DATA IN THIS EXAMPLE
rng("default") %For reproducibility
row=1000;
col=8;
profit = rand(row,col);
c3 = randi(size(profit,2),row,col);
maxcat = 3;
group=row-1; %group must to be <row)
c3(rand(group,col)<0.4)=0; % i use this code to turn off some element in c3
%*****************************THIS IS CODE TO VELOCIZE
fr = ones(size(profit));
tic
for r=1:row
for x=1:group %(rank group)
z=c3(x,c3(x,:)>0); %find element >0
A=profit(r,z);
[~,idxx]=sort(A,'descend');
idxxx=idxx(maxcat+1:end);
if ~isempty(idxxx)
fr(r,z(idxxx))=0;
end
end
end
origTime = toc
origTime = 4.2989
fr = ones(size(profit));
% vectorize method
tic
[~,j,c] = find(c3(1:group,:)');
c = accumarray(j, c, [], @(i){i});
k = max(cellfun(@height, c)-maxcat, 0);
[~, j] = arrayfun(@(c,k)mink(profit(:,c{1}), k, 2), c, k, 'unif', 0);
cj = cellfun(@(c,j) c(j), c, j, 'unif', 0);
fr((1:row)' + row*([cj{:}]-1)) = 0;
vectorTime = toc
vectorTime = 0.1545
fprintf("Vectorised method is %f times faster\n",origTime/vectorTime);
Vectorised method is 27.815283 times faster
pipin
pipin 2023-8-8
good work ..thank you

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