MATLAB: Problem in running time of the project

run time problem

hi, my project running time make me crazy.
I write a script with only 3 " for " but when I click on run button it takes 166 second to run that.
I try it in other computers and Ihave same problem so I realize that the problem is in my script.
with same inputs my friend write another script and we both get same output but his script ran in 3 seconds and my script runs in 166 seconds. (why?) (we have same laptops)
my laptop's specs :
cpu = corei7 5500U
ram = 8 GB
here is my code please tell me where is the problem that I cant get answer in few seconds.
clc
clear
tic;
Input = [ 5     12      0.02
          4     20      0.1
          6     50      0.01
          4     76      0.02
          3     100     0.04
          4     155     0.04
          3     197     0.05
          1     350     0.08
          2     400     0.12];
      
n=Input(:,1);
cap=Input(:,2);
FOR=Input(:,3);
COPT=zeros;
copt1=zeros;
Prob=zeros;
%copt 1
for i=0:n(1)
    copt1(i+1,1) = cap(1)*i;
    copt1(i+1,2) = (nchoosek(n(1),i))*(FOR(1)^(i))*((1-FOR(1))^(n(1)-i));
    
end
    
l=1;
for i=1:size(copt1,1)
    COPT(l,1)=copt1(i,1);
    COPT(l,2)=copt1(i,2);
    l=l+1;
end
%problem is starts from here
for i=2:size(cap,1)
    a=size(COPT,1);
    for j=1:n(i)
        for k=1:a
            COPT(l,1)=cap(i)*j + COPT(k,1);       
            l=l+1;
        end
    end
end
toc;

Best Answer

I changed one simple thing, it was working more efficiently for me:
clc
clear;
tic;
Input = [ 5     12      0.02
4     20      0.1
6     50      0.01
4     76      0.02
3     100     0.04
4     155     0.04
3     197     0.05
1     350     0.08
2     400     0.12];
n=Input(:,1);
cap=Input(:,2);
FOR=Input(:,3);
COPT=zeros;
copt1=zeros;
Prob=zeros;
%copt 1
for i=0:n(1)
    copt1(i+1,1) = cap(1)*i;
    copt1(i+1,2) = (nchoosek(n(1),i))*(FOR(1)^(i))*((1-FOR(1))^(n(1)-i));
end
COPT  =copt1(:,1); % I removed second loop and in place made COPT a column vector
l=size(COPT,1)+1; 
for i=2:size(cap,1)
    a=size(COPT,1);
    for j=1:n(i)
        for k=1:a
            COPT(l,1)=cap(i)*j + COPT(k,1);
            l=l+1;
        end
    end
end
COPT(:,2) = zeros(size(COPT,2));
COPT(1:6,2) = copt1(:,2);
toc;
I believe this is something to do with not prelocating the size of an array, MATLAB uses more memory and bigger the dimesion of the matrix more is the time taken to change the size of it. Let me know if this works for you .
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