How to create a matrix with while loop?

Question

Teb Keb 2022-2-15

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1649925-how-to-create-a-matrix-with-while-loop

评论： Teb Keb 2022-2-15

I have a problem where I have to calculate the time it will take for a fluid to leave a container using while loop and give the results in matrix array at every 0.10 second increments. This is the code I have so far:

v0=20;
A=3000;
t = 0;
m = [];
while vol<0
    t=t+0.10;
    vol=A-vol0*t;
    m = [m;t,vol];
end

Basically my matrix should be something like:

 %t      %vol
  0     2000
0.10    1000
0.20     500
 t        0
% until vol becomes 0 and I want to find the time t when it becomes 0.

But somehow my matrix is 0x0. I can only create a matrix if I set the time to be known.

I know that it is inefficient to use while loop for this case. But I want to learn to create a matrix from while loop using this example.

Thank you,

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Answer 1

KSSV 2022-2-15

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1649925-how-to-create-a-matrix-with-while-loop#answer_896240

在 MATLAB Online 中打开

vol=20;
A=3000;
t = 0;
m = zeros([],2) ;
iter = 0 ; 
while vol>0
    iter = iter+1; 
    t=t+0.10;
    vol=A-vol*t;    
    m(iter,:) = [t,vol];
end
m