Creating a new matrix in each iteration

Question

E K 2012-7-28

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/44746-creating-a-new-matrix-in-each-iteration

采纳的回答： per isakson

Hey guys,

I am trying to create a new matrix in each iteration.

something like

for i=1:n

somerandommatrix(n)(i,j)=[x,y];

end

anyone know how to do such thing?

Thanks in advance.

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E K 2012-7-28

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Sorry if i am not clear enough, what i am trying to do is creating a matrix named coveredrtp for the first possible base site , do the same thing for j=2 (a second possiblebase site which contains (x.y) coordinates than check it with the first one how many elements they share in common. Then for the third possiblebasesite position i want to make this comparision with first and second one.

In a more mathematical explanation

i want to check coveredrtp(i,:) for possiblebasestation(x,y) with every coveredrtp(j,:) where j<i. And here is my loop if it will help;

and sizes of matrix will stay same in columns because it will represent coordinates but it can change in manner of number of rows.

thank you again

 if true
 for j=1:length(possiblebasesite)
 xtest=possiblebasesite(j,1);
 ytest=possiblebasesite(j,2);
    for i=1:numberofrtp
        if (rtpposition(i,1) <= xtest+radius||rtpposition(i,1) <= xtest-radius)...
                && (rtpposition(i,2) <= ytest+radius||rtpposition(i,1) <= ytest-radius)
            if sqrt( ((xtest-rtpposition(i,1))^2) + ((ytest-rtpposition(i,2))^2)) <= radius
                coveredrtptest(k,1)=rtpposition(i,1);
                coveredrtptest(k,2)=rtpposition(i,2);
                k=k+1;
            end
        end
    end

end end

per isakson 2012-7-28

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BTW:

    if false
    ...
    ...
    end

used to be a trick to "comment out" block of code. Now that is better done with

    %{
    ....
    ....
    %}

which Matlab understand and turns the "comments" green. More readable - fewer mistakes.

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Answer 1

per isakson 2012-7-28

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/44746-creating-a-new-matrix-in-each-iteration#answer_54825

编辑：per isakson 2012-7-28

在 MATLAB Online 中打开

Since we don't know the size of coveredrtptest beforehand it is a bit tricky to preallocate it.

This will give you a cell array, somerandommatrix, the elements, coveredrtptest, of which are double arrays.

    len = length(possiblebasesite);
    somerandommatrix = cell( len, 1 );  % allocate memory
    for jj=1:len
        coveredrtptest = [];
        for ii=1:numberofrtp
            if ...
                if ...
                    coveredrtptest(end+1,1:2)=rtpposition(ii,1:2);
                end
            end
        end
        somerandommatrix{jj} = coveredrtptest;
    end