For Loop to concatenate Matrix Product

Question

Laurel Castillo 2018-12-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/433346-for-loop-to-concatenate-matrix-product

回答： Bruno Luong 2018-12-2

Hi,

So the matrix A_All will expand in each loop by adding a 4*4 matrix at the end. The 4*4 matrix is generated from some calculation with i.

Let T_i be the 4*4 matrix in i-th loop,

after the 5-th iteration, A_All = [T_1; T_2; T_3; T_4; T_5]

Now I also want a matrix A_0toAll = [T_1; T_1*T_2; T_1*T_2*T_3; T_1*T_2*T_3*T_4; T_1*T_2*T_3*T_4*T_5] after 5-th iteration.

A_All = [];
% doesn't work: A_0toAll = [1 1 1 1; 1 1 1 1;1 1 1 1; 1 1 1 1];
for i=1:5
    
    A_All = [A_All; [i+2 i+3 i+4 i+5;
                     i+3 i+4 i+5 i+6;
                     i+4 i+5 i+6 i+7;
                     0 0 0 1
                     ]
             ];
    
    T_i = A_All( 4*(i-1)+1 : 4*i , 1 : 4 );
    
    A_0toAll = ??
    % doesn't work: A_0toAll = [(A_0toAll); (A_0toAll)*T_i];
  
end

I tried with what stated in the comments. The result does include all the matrix products I wanted, but it expotentailly produces many other unwanted matrix. I did go with it for further calculation but it exceeds maximum array size preference. So I have to make it neat!

Now I am back to this step and feel quite frustrated......

Please help!

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Answer 1

Bruno Luong 2018-12-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/433346-for-loop-to-concatenate-matrix-product#answer_350099

在 MATLAB Online 中打开

A_All = [];
A_0toAll = [];
C_i = 1;
for i=1:5   
    T_i = [i+2 i+3 i+4 i+5;
           i+3 i+4 i+5 i+6;
           i+4 i+5 i+6 i+7;
            0  0   0   1];
    A_All = [A_All; T_i];    
    C_i = C_i*T_i;
    A_0toAll = [A_0toAll; C_i];
end