Combining vectors in a for loop to form a final matrix

Question

Scott Banks 2023-7-20

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1998573-combining-vectors-in-a-for-loop-to-form-a-final-matrix

评论： Mathieu NOE 2023-7-20

Hi there,

I am writing a script to solve problems using the Moment Distribution Method for structural analysis. I have 4 loops that generate row vectors. What I want to do is combine the final calculated vectors into one large matrix. Here is the code:

DF = [0 0.625 0.375 0.6 0.4 0];
FEM = [-10 10 -18 12 -16 16];
MBal = [FEM(2)+FEM(3) FEM(4)+FEM(5)];
if MBal < 0
    MBal = abs(MBal);
end
Fdistribution = [0 DF(2:3)*MBal(1) DF(4:5)*MBal(2) 0];
for i = 1:4
Fdistribution([1,2,3,4,5,6]) = Fdistribution([2,1,4,3,6,5]);
Carry_over = Fdistribution./2;
idistribution = [ 0 Carry_over(3).*DF(2:3) Carry_over(4).*DF(4:5) 0];
    if idistribution >= 0
        idistribution = -idistribution;
    else idistribution = abs(idistribution);
    end
    Fdistribution = idistribution;
      if i == 4
        idistribution(1) = idistribution(2)/2;
        idistribution(6) = idistribution(5)/2;
      end
      Table = [Carry_over; idistribution]
end
Table = 2×6
    2.5000         0    1.2000    1.5000         0    0.8000
         0   -0.7500   -0.4500   -0.9000   -0.6000         0
Table = 2×6
   -0.3750         0   -0.4500   -0.2250         0   -0.3000
         0    0.2812    0.1687    0.1350    0.0900         0
Table = 2×6
    0.1406         0    0.0675    0.0844         0    0.0450
         0   -0.0422   -0.0253   -0.0506   -0.0337         0
Table = 2×6
   -0.0211         0   -0.0253   -0.0127         0   -0.0169
    0.0079    0.0158    0.0095    0.0076    0.0051    0.0025

Basically I want to combine the vector 'Table' so its displays all the Table vectors together. So, I would have a 8 by 6 matrix.

Can anybody help please? Then I can manipulate the matrix and sum up the columns.

Many thanks for any help.

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Answer 1

Mathieu NOE 2023-7-20

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1998573-combining-vectors-in-a-for-loop-to-form-a-final-matrix#answer_1276273

在 MATLAB Online 中打开

For small tables / arrays I don't pay too much attention to preallocation (but it's important if you are dealing with large data !!)

so the basic approach here is simply to concatenate your results

DF = [0 0.625 0.375 0.6 0.4 0];
FEM = [-10 10 -18 12 -16 16];
MBal = [FEM(2)+FEM(3) FEM(4)+FEM(5)];
tmp = [];
Table = [];
      
if MBal < 0
    MBal = abs(MBal);
end
Fdistribution = [0 DF(2:3)*MBal(1) DF(4:5)*MBal(2) 0];
for i = 1:4
Fdistribution([1,2,3,4,5,6]) = Fdistribution([2,1,4,3,6,5]);
Carry_over = Fdistribution./2;
idistribution = [ 0 Carry_over(3).*DF(2:3) Carry_over(4).*DF(4:5) 0];
    if idistribution >= 0
        idistribution = -idistribution;
    else idistribution = abs(idistribution);
    end
    Fdistribution = idistribution;
      if i == 4
        idistribution(1) = idistribution(2)/2;
        idistribution(6) = idistribution(5)/2;
      end
      tmp = [Carry_over; idistribution];
      Table = [Table; tmp];
end
Table
Table = 8×6
    2.5000         0    1.2000    1.5000         0    0.8000
         0   -0.7500   -0.4500   -0.9000   -0.6000         0
   -0.3750         0   -0.4500   -0.2250         0   -0.3000
         0    0.2812    0.1687    0.1350    0.0900         0
    0.1406         0    0.0675    0.0844         0    0.0450
         0   -0.0422   -0.0253   -0.0506   -0.0337         0
   -0.0211         0   -0.0253   -0.0127         0   -0.0169
    0.0079    0.0158    0.0095    0.0076    0.0051    0.0025