How to create a loop in matlab codes?

i am calculating a variable theta , and i need to give this theta as a feed bak to one of the formula which i used to calculate it. how should i give a loop. i am totally new to matlab codes. please help. the calculation is,

theta = a+b-c-d, where a b c d are some formulas, in which b and c has a theta term in it. so i have to give the left side theta as feedback to b and c.

in simulink you can just pick a line from theta and connect it to b and c block. but how do i loop this with matlab codes?

please help me.

Answer 1

[Thorsten]

theta = 23; % some starting value
for i = 1:10 % run 10 times, for example
  a = exp(i); % sample computations for a, b, c, d
  b = sin(i);
  b = 10*theta
  c = theta^2;
  theta = a + b - c - d;
end

[Heartrin]

Hi thorsten,

doesn't theta need some initial values to start the first iteration.

[Thorsten]

yes, sure. I added it in the code.

[Heartrin]

Hi thanks for your help. but i have a doubt what is that (i) in the sample computation of a & b in the codes you written above?

[Thorsten]

i is the loop variable that runs from 1:10, i.e., takes values 1, 2, 3, ..., 10. You can use x instead of i if you do not want to overwrite the Matlab's constant for the imaginary unit i=sqrt(-1).