How to set stopping condition on time in nested for loop?

tic
Time = 0;
 flag = 0;
for kk = 1: n
some operations
for ii = 1:m 
    if Time >= Time_limit
       flag = 1;
        break
    end
  some operations
end
Time = toc;
if(flag==1)
          break
end
end

But the above code does not stop when a time limit reached.

Answer 1

[Walter Roberson]

tic
Time = 0;
for kk = 1: n
    some operations
    for ii = 1:m 
        Time = toc;        %you just did some work, you might have reached the limit
        if Time >= Time_limit; break; end
      some operations
    end
    Time = toc;        %you just did some work, you might have reached the limit
    if Time >= Time_limit; break; end
end

The second call to toc is because you might have done some work when ii == m that put you over the time limit. There is no toc just before the end of the for ii loop so in the case where you left the for loop because you ran out of iterations, you have not updated the time.

Answer 2

[David Hill]

tStart = cputime;
c=0;
while 1
    if cputime-tStart>20
        break
    end
    c=c+1;
end
c

c = 23672107

[Walter Roberson]

A question would be whether to stop based on cpu time or based on elapsed time.

[Noor Fatima]

Based on elapsed time

[Noor Fatima]

@David Hill Thank you for your answer but I want to find elapsed time with in double for loop.