MATLAB: How would i make the for loop stop calculating when it calculates F <= 0? I want the for loop to stop writing. values in F when it hits 0 or less. I have tried "break", but can not seem to get it to work.

for looploop

 n = 10;        
 terskelverdi = 0.1;
 F = zeros(n,1); 
 F(1) = 1;
 F(2) = 1;
 for k = 3:n 
     r = rand(1); 
     if r > terskelverdi
     F(k) = F(k-1) + F(k-2); 
     else
     F(k) = F(k-1) - F(k-2); 
   end
 end
     if F > 0     
         disp(F)
         figure, plot(F), grid
         title('Fibonaccitall med tilfeldigheter opp til "n"')
     else 
         disp('Kaninbestanden er utryddet')
     end

Best Answer

You should simply check F(k), inside your loop,
 for k = 3:n 
     r = rand(1); 
     if r > terskelverdi
     F(k) = F(k-1) + F(k-2); 
     else
     F(k) = F(k-1) - F(k-2); 
     end
     if F(k)<=0
         F(k) = 0; %if you want to set the last found value to 0
         break
     end
 end
or, after you calculate F, you could set all the negative to 0 (but I don't know if you'd like it this way for your actual problem)
 F(F<=0)=0;
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