Anybody knows how to do to this script goes faster?

Hi, everybody.

I just would like to know if is possible make this script goes faster. It is part of one study about lottery, and it is taking too much time to process. Anybody can help me?

% In this lottery, 15 numbers out of 25 (1 to 25) are drawn. You can win
% specific prizes if you match 11 numbers, or 12 numbers, or 13 numbers,
% or 14 numbers, or 15 numbers.

b = 0; v = 0;

v = 1:25;
combinations = nchoosek(v,15); % matrix with 3268760 lines with all
                               % combinations possible to 15 numbers
                               % chosen between 1 and 25.

lottery = randi(25,2400,15); %simulates 2400 draws for this lottery

number_of_combinations = size(combinations,1); %3268760
number_of_draws = size(lottery,1); %2400


registers = zeros(number_of_combinations,7);

for b = 1:number_of_combinations
    registers(b,1) = b;
end


won15 = 0; won14 = 0; won13 = 0; won12 = 0; won11 = 0;
hit = 0;
i = 0; j1 = 0; j2 = 0; k = 0;

for i = 1:number_of_combinations
    
    for k = 1:number_of_draws
        
        for j1 = 1:15
            
            for j2 = 1:15
                
                if combinations(i,j1) == lottery(k,j2) %check how many times each combinations
                                                       % won some prize considering all 2400 draws
                    hit = hit+1;
                end
                
            end
            
            if hit == 15
                won15 = won15+1;
                registers(i,2) = k; %won the biggest prize in what draw?
                registers(i,3) = won15; %won with 15 numbers how many times?
            end
            
            if hit == 14
                won14 = won14+1;
                registers(i,4) = won14; %won with 14 numbers how many times?
            end
            
            if hit == 13
                won13 = won13+1;
                registers(i,5) = won13; %won with 13 numbers how many times?
            end
            
            if hit == 12
                won12 = won12+1;
                registers(i,6) = won12; %won with 12 numbers how many times?
            end
            
            if hit == 11
                won11 = won11+1;
                registers(i,7) = won11; %won with 11 numbers how many times?
            end
            
        end
        hit = 0;
    end
    
    
    won15 = 0;
    won14 = 0;
    won13 = 0;
    won12 = 0;
    won11 = 0;
    
end

In this code I check how many times each combination possible won considering all 2400 draws.

Att,

Paulo

Answer 1

[Rik]

Using ismember will already speed up your loop by a lot. The point is that you are analysing a lot of data, so it just will take a very long time. About 8 hours on my machine assuming constant speed.

% In this lottery, 15 numbers out of 25 (1 to 25) are drawn. You can win
% specific prizes if you match 11 numbers, or 12 numbers, or 13 numbers,
% or 14 numbers, or 15 numbers.

v = 1:25;
combinations = nchoosek(v,15); % matrix with 3268760 lines with all
% combinations possible to 15 numbers
% chosen between 1 and 25.

lottery = randi(25,2400,15);

number_of_combinations = size(combinations,1);
number_of_draws = size(lottery,1);
registers = zeros(number_of_combinations,9);
registers(:,1)=1:number_of_combinations;
won15 = 0; won14 = 0; won13 = 0; won12 = 0; won11 = 0;

tic
for n = 1:number_of_combinations
    for m = 1:number_of_draws
        hits=sum(ismember(lottery(m,:),combinations(n,:)));
        switch hits
            case 15
                won15 = won15+1;
                registers(n,2) = m;
                registers(n,3) = won15;
            case 14
                won14 = won14+1;
                registers(n,4) = won14;
            case 13
                won13 = won13+1;
                registers(n,5) = won13;
            case 12
                won12 = won12+1;
                registers(n,6) = won12;
            case 11
                won11 = won11+1;
                registers(n,7) = won11;
        end
    end
    break
end
t=toc*number_of_combinations;
t=[floor(t/(60*60)) floor(mod(t,60*60)/60) mod(t,60)];
fprintf('approximate duration: %d:%02d:%.1f\n',t)

approximate duration: 22:57:46.9

[Paulo Cunha]

Awesome!! Your solution really made the processing time shorter and I learned a lot with it. Thank you very much!