Stop Itration of a matric when it converges

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Salman Saeed 2015-8-24

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评论： Salman Saeed 2015-8-28

My matrix is iterating with each element using same equation. I want to stop the iteration at convergence. My code (below) is not stopping no matter what. Can someone please help me out?

probability = (ones(1,2048) .* 1/2048);
Tij = sum(StateTransitionfwd);
Tji = sum(StateTransitionbwd);
 p = ((Tji .* probability) - (Tij .* probability));
threshold = (zeros(1,2048));
old = p;
new = zeros(1,2048);
 while true
    p = ((p * StateTransitionbwd) - (Tij .* p));
    new = p;
        if old-new <= threshold
          break
        end
      old = p;
   %old - new = threshold;
end

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Answer 1

Walter Roberson 2015-8-24

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https://ww2.mathworks.cn/matlabcentral/answers/235646-stop-itration-of-a-matric-when-it-converges#answer_190162

在 MATLAB Online 中打开

Try

if abs(old-new) <= threshold

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Walter Roberson 2015-8-24

在 MATLAB Online 中打开

You appear to be working with vectors. When you use "if" with a vector condition, the "if" is only considered true if all of the entries in the vector are true. If that is what you want, then it is recommended that you code it specifically using all() as in

if all(abs(old-new) <= threshold)

as that way people reading the code will know that you have specifically thought about this difficulty.

If you want to stop the loop if at least one of the entries in the vector is true, then use the line as above but replace all() with any()

If you do want the execution to proceed until all() of the conditions are met, you need to analyze to see if that is even possible.

I do not follow exactly what you are doing with the subtraction in the determination of the new p, but it looks a bit odd to me that you are calculating the sum of the Forward transition matrix and mixing that with the Backwards transition matrix. Plausibly that is correct, but I would naively expect the Backwards sum Tji to be used with the Backwards Transition matrix. A comment would be good there.

Salman Saeed 2015-8-28

3755.pdf

Basically I am working on the cell cycle. I am attaching the paper I am working on. Please have a look at equation 4 and its description. I have the transition probabilities of all the states. So basically in this loop I am trying to iterate equation 4.

Thank you so much for helping me out.

Salman Saeed 2015-8-28

salman.m

and here is my code

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Stop Itration of a matric when it converges

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Stop Itration of a matric when it converges

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