How to iterate this

Hi,

I need to iterate a series of equation for a problem. In particular I want to iterate them for 12 times. For the very first iteration I want to put two conditions (Lambda1dotZero=0 and Lambda=0); then from the second iteration onward Lambda1dotzero must be equal to the value of Lambda1dotZero of the previous iteration + a certain value DeltaOmega (which I know, and is constant). The same for Lambda, which from the second iteration onward, must be equal to that equation that you see in the loop (Lambda(m)=.....) + the value of Lambda of the previous iteration. Sorry but I am very new in Matlab, and this is the code that I wrote:

for m=1:1:12
  while m==1;
      Lambda1dotZero(m)=0;
      Lambda(m)=0;
      Lambda1dot(m)=Lambda2dot*t_days+Lambda1dotZero(m);
      Lambda(m)=Lambda2dot*t_days^2/2+Lambda1dotZero(m)*t_days+Lambda(m);
  end

    while m>1;
        Lambda1dotZero(m)=Lambda1dotZero(m-1)+DeltaOmega;
        Lambda1dot(m)=Lambda2dot*t_days+Lambda1dotZero(m);
        Lambda(m)=Lambda2dot*t_days^2/2+Lambda1dotZero(m)*t_days+Lambda(m-1);
    end
  end

When I run it, it doesn't give me errors but takes a long time without giving any results. Maybe I have created an infinite loop. I don't know. Many thanks to anyone who will help me.

Regards

Gian

Answer 1

[Walter Roberson]

for m=1:1:12
  if m==1
      Lambda1dotZero(m)=0;
      Lambda(m)=0;
      Lambda1dot(m)=Lambda2dot*t_days+Lambda1dotZero(m);
      Lambda(m)=Lambda2dot*t_days^2/2+Lambda1dotZero(m)*t_days+Lambda(m);
  end

    if m>1
        Lambda1dotZero(m)=Lambda1dotZero(m-1)+DeltaOmega;
        Lambda1dot(m)=Lambda2dot*t_days+Lambda1dotZero(m);
        Lambda(m)=Lambda2dot*t_days^2/2+Lambda1dotZero(m)*t_days+Lambda(m-1);
    end
  end

Remember, a while loop executes its body until the condition is false and does not go on to the next section until then, but since m was not changing in the body, your while loop was infinite.

[Gianluca]

Thank you very much for your help man. The problem was about the motion of a satellite, and the results that Matlab gives me seem right. So the code works perfectly! Also now I understand how the while loop works ;)

Thanks again

Regards

Gian