I want to run a loop until a value is reached and, then, I want to use that reached value to continue the loop

Hi everyone! Thanks for helping.

I'm running a code about hydrogeology. I'm calculating tha saturated portion of a soil depending on rainfall amount.

I need Matlab to calculate this saturated thickness until a certain value H is reached. This value is the maximum depth of the soil of course.

When the loop reaches H, I want Matlab to keep on doing the calculations assuming H as the new starting point, instead of the value > H that it has been encountered.

How can I do this? Thanks for helping!

Answer 1

[Voss]

Hard to say for sure, but maybe some structure like this (but with a break condition - which was unspecified in the question):

H = 100;
thickness = 0;
while true
    thickness = thickness+1;
    if thickness >= H
        thickness = thickness-H;
    end
end

Answer 2

[jjjSAN]

Many many thanks!! Finally I managed by doing this:

ii = 1;
m(1) = m0;
deltam(1) = 0;
output(1) = 0;

while true
    ii = ii + 1
            output(ii) = prod*m(ii-1);
            deltam(ii) = ((input(ii)-output(ii))./den2(ii));
            m(ii) = (m(ii-1) + deltam(ii));
            if m(ii) >= H;
                m(ii) = H;
            end
end

[jjjSAN]

It onyl reports this:

''Index exceeds the number of array elements. Index must not exceed 1013.''

[Voss]

You don't want the code to run forever, do you? You have to put in some condition for the while loop to stop (or a break condition, like I said in my answer), e.g.:

ii = 1;
m(1) = m0;
deltam(1) = 0;
output(1) = 0;

N = numel(input);
while ii < N
    
    ii = ii + 1
    output(ii) = prod*m(ii-1);
    deltam(ii) = ((input(ii)-output(ii))./den2(ii));
    m(ii) = (m(ii-1) + deltam(ii));
    if m(ii) >= H;
        m(ii) = H;
    end
    
end

I don't know if that's the correct condition without knowing anything about your variables.

[jjjSAN]

Finally I just added an if loop inside the code I posted earlier:

if ii > a (a was the length of my dataset)

break

end

And so it runs normally now :D

[Voss]

Sounds good!