find pivot points of a matrix in matlab

To find the pivot points of a matrix in MATLAB, you can use the rref function to calculate the reduced row echelon form of the matrix. The pivot points are the indices of the columns that contain the leading 1's in the row echelon form.

Here is an example code:

main.m
% create a sample matrix
A = [1 2 3; 4 5 6; 7 8 9];

% calculate the row echelon form of A
rref_A = rref(A);

% find the pivot points
pivot_points = [];
for i = 1:size(rref_A, 2)
    col = rref_A(:, i);
    if sum(col) == 1 && col(i) == 1
        pivot_points = [pivot_points i];
    end
end

disp(pivot_points);
313 chars
17 lines

In this code, we create a sample matrix A. We then calculate the row echelon form of A using the rref function, and store it in rref_A.

We then loop over each column of rref_A, check if the column contains a leading 1, and store the index of any columns that do contain a leading 1 in pivot_points. Finally, we print the pivot_points array to the console.

When we run this code, we should see the output:

main.m
1   2
6 chars
2 lines

This indicates that the pivot points of the matrix are in columns 1 and 2.