How to save a maxtrix created by for loop

Question

jaehun chung 2023-3-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1928420-how-to-save-a-maxtrix-created-by-for-loop

编辑： Biraj Khanal 2023-3-19

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The code below is what I write to interpolate the function.

To plot the interpolated function, I think fx should be saved in 49 columns.

How can I put fx in a matrix? (1 row and 49 columns)

--------------------------------------------------------

x=linspace(-2,2,13);
xi=linspace(-2,2,49);
f= 3*x.^2 + 8*x;
m = [-1 -0.5 0 0.5 1];
fx=zeros(size(xi));
for i = 1 : length(x) -1
    for j = 1 : length(m)
        fx = f(i) * (1-m(j)) / 2 + f(i+1) * (1+m(j)) / 2
    end  
end
plot(xi,fx,'*-')

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Answer 1

Biraj Khanal 2023-3-14

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https://ww2.mathworks.cn/matlabcentral/answers/1928420-how-to-save-a-maxtrix-created-by-for-loop#answer_1192750

在 MATLAB Online 中打开

Is this what you are trying to do?

x=linspace(-2,2,13);

xi=linspace(-2,2,49);

f= 3*x.^2 + 8*x;

fx = interp1(x,f,xi);

plot(xi,fx)

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jaehun chung 2023-3-16

thanks but it is not what I want.

Im trying to plot the interpolated function without using 'interp1'.

Biraj Khanal 2023-3-19

编辑：Biraj Khanal 2023-3-19

Your length(x) -1 is 12 and length(m) is 5. hence if you put fx in a matrix by assigning a counter c and increase it in every iteration, you would obtain fx with 60 elements. I am not sure how you are trying to relate it with xi. Can you clarify?

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