While loop

Question

Dougie 2012-5-3

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/37255-while-loop

Hoping somebody could help me fix my while loop.

Whilst the output to a function Convergence == 0 i want the while loop to continue to iterate, producing an output matrix R_2, and also updating the run_number to run_number + 1. It's not necessary to store the previous matrices, if it's faster to run then the matrices could be replaced.

Here's what i have so far.

R_2 = %%not sure what goes here. 
Conv = 0;   %initially convergence criteria = 0
run_number = 1;
R_2{run_number} = R_2;
while Conv == 0
      R_1 = %%%%function producing R_!;
Radius = %%function producing 
R_2{run_number} = %function of R1 and Radius
Conv{run_number} = Conv(R_2{run_number});
run_number = run_number+1;
end

Thanks a lot

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Answer 1

Walter Roberson 2012-5-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/37255-while-loop#answer_46536

在 MATLAB Online 中打开

Conv{1} = 0;  %instead of Conv = 0;
while Conv{end} == 0

and use

Conv{run_number} = Conv{R_2{run_number}}; %instead of Conv()

However, please examine this statement more carefully:

Conv{run_number} = Conv{R_2{run_number}};

On the first iteration, Conv{1} is the only thing that exists, so if R_2{1} is not exactly 1 then you would be accessing out of bounds. So R_2{1} must be 1, and you are then setting Conv{1} = Conv{1} and that was initialized to 0. Second iteration, Conv{1} is still the only thing that exists, so R_2{2} must be 1, and you are setting Conv{2} = Conv{1} which is 0. Third iteration, the existing Conv{1}=0 and Conv{2}=0 are what exists, so Conv{3}=0. By induction, you are going to continue the loop with 0's until you run out of memory.