Changing the parameters of a for loops if condition is met

Hi All,

was wondering if you could shed some light on an issue, i have read other breaking of for loops but got lost with the explanation or size of the code in the example. I have a simplified version of my code below which is for running total temperature rise.

NOC =2; % number of cycles
RT=zeros(100,NOC); % running temp total
RT(1,1)=20 % starting ambient temp
for Y = 1:NOC
  for x = 1:100
    if x==1 && Y>1
      RT(x,Y)=RT(end,Y-1);
    end
    value(x) = 2*x;
    if x ~=1
      RT(x,Y) = value(x) +RT(x-1,Y)
    end
  end
end

I want to add in a temperature parameter which if met, changes to a different line of code and continues, so if the RT value is greater than 1000, stop multiplying it by 2 and start multiplying it by 5 etc. I've seen as much as its not as easy to break a for loop than others but when i try, if,break and continue i am doing something wrong and it is not seeing the condition i have set as met to execute the different line of code.

Thank you in advance for any help.

[dpb]

Your condition of RT>Tset isn't tied directly to the value at which you want the change to occur so breaking on the loop really isn't what you need here in all likelihood.

You don't show the code you tried but more fruitful approach would likely be to make the multiplier a variable and set it's value based on the value of RT(x,Y) before the multiply; then there's no branching needed, just use the (already computed) multiplier.

[Jo Betteley]

Thank you for your response, this is what i am currently trying. A better representation of my code is this:

 NOC =2; % number of cycles
 RT=zeros(100,NOC); % running temp total
 RT(1,1)=20 % starting ambient temp

 SHW =4.5; % specific heat capcaity of water
 LPM = 5; % litres per minute flow rate
 FR= LPM/60; % litres per minute into kg/s
 Q=1 % heating of 1kW

 for Y = 1:NOC

    for x = 1:100
        if x ==1 &&Y>1
           RT(x,Y) =RT(end,Y-1);
        end

        if x ~=1

            TR(x,Y) = Q/(SHW*FR)

            RT(x,Y) = TR(x,Y) +RT(x-1,Y)

            if RT(x,Y) > 50
                 TR(x,Y) = (Q/(SHW*FR))*1000

                 RT(x,Y) = TR(x,Y) +RT(x-1,Y)
            end
        end

    end
end

So for temperature under 50 degrees i have the code running:

 TR(x,Y) = Q/(SHW*FR)
 RT(x,Y) = TR(x,Y) +RT(x-1,Y)

Then for temp above 50 i have it switch to:

 TR(x,Y) = (Q/(SHW*FR))*1000
 RT(x,Y) = TR(x,Y) +RT(x-1,Y)

The * 1000 is just so i could see the value change. I think this is now working.....I think

[dpb]

Actually, for RT<=50 you have both branches being taken. Superficial read indicates that doesn't really matter for this specific code; it just overwrites the previous answer, but is dangerous if something else were to change.

Answer 1

[dpb]

...
Q=1               % heating of 1kW
QMult=[2 5];      % choices from original posting 
for Y = 1:NOC
  for x = 1:100
    if x ==1 &&Y>1
      RT(x,Y) =RT(end,Y-1);
    end
    if x ~=1
      QFact=Qmult(RT(x,Y)>50 +1);       % lookup desired factor from previous temp
      TR(x,Y) = Q/(SHW*FR)*QFact;
    end
  end
end
...

[Jo Betteley]

Ah, great stuff, i have just been having a play with that and it works, just got to make sense of the rest of the code ive got.

thank you very much for the help!