Function for reduced row Echelon form / Solving linear equations

1

Here’s a function that converts a matrix to its reduced row echelon form in case someone needs it for solving linear equations through Gaussian ellimination.
The original algorithm is from: https://rosettacode.org/wiki/Reduced_row_echelon_form

(
~toReducedRowEchelonForm = { |matrix|
	var lead = 0;
    var rowCount = matrix.size;
    var columnCount = matrix[0].size;
	var pivot, factor;

	block { |break| 
		rowCount.do { |r|
			var i;

			if (columnCount <= lead, {
				break.value(nil) ;
			});

			i = r;

			while({matrix[i][lead] == 0},
				{
				i = i + 1;
				block{|break2|
					if(rowCount == i,
						{
							i = r;
							lead = lead + 1;
							if (columnCount == lead, {
								break2.value(nil);
							});
					});
			}});

			matrix.swap(i, r);

			pivot = matrix[r][lead];
			if(pivot != 0,
				{matrix.put(r, matrix[r]/pivot)}
			);

			rowCount.do{|i|
				if(i != r, {
					var change;
					factor = matrix[i][lead];
					matrix.put(i, matrix[i] - (factor * matrix[r]));
					//matrix.postln;
				});
			};

			lead = lead + 1;
		}
	};
	matrix;
};
)
(
a = [[80, 20, 0, 0.075, 10],[20, 80, 20, 0.03, 30],[0, 0, 160, 0.045, 20]];

~toReducedRowEchelonForm.value(a);
)
1 Like
2

@erenutku97, you could consider contributing to the Matrix class found in the MathLib quark.

1 Like