How to deal with dimension of the both sides?

Unable to perform assignment because the indices on the left side are not compatible with the

size of the right side.

X1_bar_i =[9.59547499999917
              58282.181075
          35.4837749999997
              58288.903275
         -35.4750250000006
              58455.670975
         -9.60422500000095
              58462.389975]
X2_bar_i =[9.59557499999937
              58282.183075
          35.4903749999994
              58288.908875
         -35.4809250000008
              58455.676575
         -9.60502500000075
              58462.394475]
for i=1:size(X1_bar_i)
    H(i,1)= [0 X1_bar_i(i+1,1) X1_bar_i(i,1) -X1_bar_i(i+1,1) 0 1;X1_bar_i(i+1,1) X1_bar_i(i,1) 0 X1_bar_i(i,1) 1 0];
    i=i+1;
end

The dimension of the H should be 2*6. How can I do it?

[Nikhil Sapre]

Can you explain what do you mean by the dimension of the H should be 2*6? Why?

How is H formed? Can you elaborate with a simple example?

[Scott MacKenzie]

In MATLAB, the loop index variable in a for-loop cannot be changed via code in the loop. So, the line

i = i + 1; 

has no bearing on the value of the variable i as used in the loop.

Other issues... X1_bar_i is a vector, not a matrix. Accessing elements require one index, not two.

Also, accessing the element in position i+1 of X1_bar_i is not possible in the last iteration when i is equal to the length of the vector. That is an attempt to access the element past the end of the vector, which is not possible.

So, there are a few issues to think about here. Good luck.

Answer 1

[DGM]

Start here

X1_bar_i =[9.59547499999917
              58282.181075
          35.4837749999997
              58288.903275
         -35.4750250000006
              58455.670975
         -9.60422500000095
              58462.389975]
X2_bar_i =[9.59557499999937
              58282.183075
          35.4903749999994
              58288.908875
         -35.4809250000008
              58455.676575
         -9.60502500000075
              58462.394475]
		  
% preallocate.  
% since each iteration calculates a 2D array, i'm going to stack them on dim3
% if you want them edge-concatenated, you'll have to make that change.
H = zeros(2,6,size(X1_bar_i,1)-1);
% size(X1...) is [8 1].  pick one dimension explicitly, or use numel()
% since array indexing offsets +1, i can't extend to the end
% don't know if that's what you were hoping for
% for i=1:size(X1_bar_i) 
for i = 1:size(X1_bar_i,1)-1
    H(:,:,i) = [0 X1_bar_i(i+1) X1_bar_i(i) -X1_bar_i(i+1) 0 1;
        X1_bar_i(i+1) X1_bar_i(i) 0 X1_bar_i(i) 1 0];
    % i=i+1; % this doesn't do anything.  don't set the loop iterator inside the loop
end