how to count number of iterations.?

9 次查看（过去 30 天）

Nimisha 2014-12-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/166821-how-to-count-number-of-iterations

评论： Adam 2014-12-16

 I = imread('Coins.jpg');
Id = im2double(I); % I is a uint8 grayscale image
T = 0.5*(min(Id(:)) + max(Id(:)));
deltaT = 0.01; % convergence criterion
done = false;
 while done
g = Id >= T;
Tnext = 0.5*(mean(Id(g)) + mean(Id(g)));
done = abs(T - Tnext) < deltaT;
T = Tnext;
end

i want to count number of iteration for this program.! as well i want to store value of T at each iteration.!

2 个评论
显示无隐藏无

Nimisha 2014-12-16

在 MATLAB Online 中打开

 I = imread('Coins.jpg');
Id = im2double(I); % I is a uint8 grayscale image
done = false;
count = 0
T = zeros(1,100); % Try to presize to something big enough to hold all iterations if you can estimate it
while done
   g = Id >= T;
   Tnext = 0.5*(mean(Id(g)) + mean(Id(g)));
   count = count + 1;
   T(count) = Tnext
end

Why we changed T.? Cant we do with previous T.?

And above is giving results as 0

Adam 2014-12-16

I edited my answer below. I didn't notice the initialisation of T higher up and the >= test against it in the while loop.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Adam 2014-12-16

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/166821-how-to-count-number-of-iterations#answer_162512

编辑：Adam 2014-12-16

在 MATLAB Online 中打开

count = 0
newT = zeros(1,100); % Try to presize to something big enough to hold all iterations if you can estimate it
while done
   g = Id >= T;
   Tnext = 0.5*(mean(Id(g)) + mean(Id(g)));
   count = count + 1;
   newT(count) = Tnext
   done = abs(T - Tnext) < deltaT;
end

Presize newT if you can come up with a sensible bounded estimate, otherwise the warning you get is likely irrelevant anyway. Your code will be a little slower, but unlikely to matter in this case.

6 个评论
显示 4更早的评论隐藏 4更早的评论

Nimisha 2014-12-16

Ya, This ~ sign works. Thank You very Much :)

Adam 2014-12-16

No problem :)

Would have been a bit quicker if I absorbed your whole original post first time, but I was trying to just scan it for the parts relevant to the question which turned out to be a mistake!

请先登录，再进行评论。