MATLAB: Create a row vector of the diagonal elements from matrix.

matrix extractionmatrix values into row vector

So I am knew to MATLAB and have a question reguarding matricies.

I'm wondeirng how to create a row vector from the diagonal values (Top left to bottom right) from a matrix (I'm using a 6×6 matrix).

Any advice would be much appreaciated.

Thanks,

Ben.

Best Answer

Meet the diag function!

Related Solutions

MATLAB: Creating a super diagonal matrix.

A gazillion ways. A few suggestions...

1. Simple is to create this as a circulant matrix. I've got a tool for that on the file exchange as I recall.

2. Or, use spdiags. This has the virtue of making it a sparse matrix.

3. Or create it as the sum of multiple diagonal matrices, each built using diag.

4. A matrix with the pattern you show can be built with a call to sparse, where you need to create a list of non-zero elements, and the row and column indices for each. This can be easier than it sounds. Again, you get a sparse result.

5. The simple pattern shown can easily enough be built using meshgrid and a test, possibly with a call to tril or triu afterwards.

Why not play with some or more of the ideas I posed above? This is the way to learn, by playing around with a goal in mind.

MATLAB: Change diagonal place

a= magic(3)
a =
       8     1     6
       3     5     7
       4     9     2
>> b=a;
>>  for i =2:size(a,1)
b(i,1:i)= fliplr(a(i,1:i));
end
b
b =
       8     1     6
       5     3     7
       2     9     4

Best Answer

Related Solutions

MATLAB: Creating a super diagonal matrix.

MATLAB: Change diagonal place

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