I see that you want to perform row pivoting operation as described in the problem statement but you are unsure about the correctness of your code.
Let us analyse the provided code:
function Matrix_Pivot=rowpivot(Matrix,y)
D=diag(Matrix); % Returns a column vector
[a,b]=max(D(y,:)); % Finding max in a vector
Matrix_Pivot=rowswap(D,b,1); % Hardcoded swap with 1st row. Infact this operation is happening in a vector
end
Analysis:
- diag(Matrix): returns a vector, not a matrix. "diag" in MATLAB returns a column vector containing all the diagonal elements. Refer to the documentation of "diag" here: https://www.mathworks.com/help/matlab/ref/diag.html
- max(D(y,:)) : is essentially finding maximum element in a column. Also for largest magnitude coefficent, absolute value must be considered.
- rowswap(D,b,1) : The row y should be swapped with the row having largest coefficent. You have hardcoded swap with the first row.
Kindly refer to the following code section below to address the potential issues with your code.
function Matrix_Pivot = rowpivot(Matrix, y)
% Get the number of rows
[n, ~] = size(Matrix);
% Extract the column from row y to n i.e. at or below the specified diagonal value
[~, maxIndex] = max(abs(Matrix(y:n, y)));
% Adjust index to match actual row in Matrix
maxRow = maxIndex + y - 1;
% Swap rows if needed
if maxRow ~= y
Matrix_Pivot = rowswap(Matrix, y, maxRow);
else
Matrix_Pivot = Matrix;
end
end
I hope this helps!
