How to position groups of matrices inside a bigger matrix

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Feliciano Döring 2018-4-30

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https://ww2.mathworks.cn/matlabcentral/answers/398304-how-to-position-groups-of-matrices-inside-a-bigger-matrix

评论： Feliciano Döring 2018-5-2

I have a program in which I have some matrices of varying size that runs through a piece of code, for the current moment i only have two matrices. What i want to know is how would i place the matrices 'M' in a bigger matrix of zeros in a way that the values always stay in the diagonal and the rest of the matrices are zeros. So, for example if a have two matrices with size 4x4 the matrix would be a 8x8 matrix with [1:4,1:4] and [5:8,5:8] being values and the rest zeros. I want to do it in a way that i can do it for n-matrices. Here is the code i use.

for iter=1:2
    D=Stations{iter};
    n=length(D);
    c=[0;0;0;0];
    rowvector=ones(1,n);
    dt0=rowvector
    dn=sqrt((D(1,:)-m0(2)).^2+(D(2,:)-m0(3)).^2+(D(3,:)-m0(4)).^2);
    dtx = -(D(1,:)-m0(2))./(v.*dn);
    dty = -(D(2,:)-m0(3))./(v.*dn);
    dtz = -(D(3,:)-m0(4))./(v.*dn);
    M=[dt0; dtx; dty; dtz];
end

'Stations' is a cell array i use to store the different matrices

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Bob Thompson 2018-4-30

Does the code work? If not what kind of errors do you get?

Will your matrices always be square?

Feliciano Döring 2018-5-1

The code works fine, The matrices will have varying size and dont always have to be square

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Answer 1

Siyu Guo 2018-5-2

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/398304-how-to-position-groups-of-matrices-inside-a-bigger-matrix#answer_318190

blkdiag function is the tool you are looking for. Help it in MATLAB. Note you can use a loop within which the function is called iteratively to cope with n sub-matrices.