Linear Algebra on DataLeafhttps://dataleaf-642346.gitlab.io/tags/linear-algebra/Recent content in Linear Algebra on DataLeafHugoen-USTue, 18 Aug 2026 00:00:00 +0000Least squares, three wayshttps://dataleaf-642346.gitlab.io/posts/least-squares-three-ways/Tue, 18 Aug 2026 00:00:00 +0000https://dataleaf-642346.gitlab.io/posts/least-squares-three-ways/Polynomial fits make the difference visible: with twelve columns, the normal equations lose every digit while QR and the SVD keep eight or nine. One identity about condition numbers explains it, and also says when the fast method is good enough.