Tag
numpy
2 posts
- LU Decomposition by Hand: Splitting a 3×3 Matrix into L·ULU decomposition is Gaussian elimination with the work saved: U is what elimination leaves behind, L records how many times each row was subtracted. Working one 3×3 matrix all the way through, then using it to solve equations and get a determinant, why row swaps are needed (PA = LU), and what it's actually good for.
- Gradient Descent, Line by Line: Twelve Lines of Python and the Calculus Behind ThemA twelve-line function fits the best straight line through a cloud of points: it starts flat at zero and 900 times over asks which way is less wrong. Taking it apart one line at a time — what a gradient actually is, where the formulas come from, why the minus sign, and what alpha does.