Store a fixed value in the variable only once-CodePudding

I have a variable in my code called p_fix. It is necessary to save the value of this variable when PE>p. But the way I did it, every time PE>p is respected, the value of this variable is changed, how can I save its value only once when PE>p and never change the value of this variable (p_fix) again?

for n = 1:size(t,1)
 if  n>=4
     X = [Ia(n-1,1) Ia(n-2,1) ; Ia(n-2,1) Ia(n-3,1)];
     future = [Ia(n,1) ; Ia(n-1,1)];
     C = X\future;
     Ia_future(n,1) = C(1,1)*Ia(n,1) C(2,1)*Ia(n-1,1);
     PE(n,1)=Ia(n,1) Ia_future(n,1);
     p(n,1)=(1 0.2)*max(PE(n-1,1));
     
 if  PE(n-1,1)>p(n,1)
     p_fix = p(n,1);

      end
   end
end

CodePudding user response：

You can either:

Before the loop, initialize p_fix to an empty array, and only set it if it’s empty:
```
if isempty(p_fix) && PE(n-1,1)>p(n,1)
   p_fix = p(n,1);
end
```
Or use a second Boolean variable, for example done, that keeps track of whether you’ve set your other variable or not. Initialize it to false before the loop, then:
```
if ~done && PE(n-1,1)>p(n,1)
   p_fix = p(n,1);
   done = true;
end
```