Saving values of a variable in while loop

I have a "while" loop for iteration and also I'm calculating error values of it. You can find it below;

while (errorVal>errorMax)

T_old=T;

for j=2:ny-1

for i=2:nx-1

T(j,i)=(1/(2*(1+beta^2)))*(T(j,i+1)+T(j,i-1)+beta^2*(T(j+1,i)+T(j-1,i)));

error(j,i)=abs(T(j,i)-T_old(j,i));

end

end

errorVal=sum(error(:));

n=n+1;

end

Here I want to save "errorVal" variable but I don't know the exact size of iteration so I cannot predefine an array for it. How can I save "errorVal" for each iteration?

Answer 1

[VBBV]

errorVal(n,:)=sum(error(:));

[Orhan Celikkaya]

It didn't work unfortunately. I want to save the value of "errorVal" at each step but this modification returns only one value.

[VBBV]

errorVal=sum(error(:));
K(n) = errorVal; 
n = n+1;

You can try storing in a variable.

[Torsten]

@Orhan Celikkaya

Shouldn't it read

T(j,i)=(1/(2*(1+beta^2)))*(T_old(j,i+1)+T_old(j,i-1)+beta^2*(T_old(j+1,i)+T_old(j-1,i)));

Or where does T_old come into play ?

Answer 2

[Torsten]

errorVal(n) = sum(error(:))/((nx-2)*(ny-2));