Math 104

Applied Matrix Theory

Fall 2008


Syllabus

The course will cover linear independence, rank, orthogonality and projections, orthonormal bases, the four fundamental subspaces of a matrix, least-squares, the QR decomposition, eigenvalues of symmetric matrices, the singular value decomposition, the condition number of a matrix, algorithms for solving linear systems.

The four 
subspaces of a matrix
Linear 
regression via least squares

The course intends to provide the mathematical background in matrix theory for modern methods of data analysis, scientific computing, and other applications to science and technology. While the choice of topics is geared towards integration with other disciplines, the emphasis of the lecture and the homework assignments will be on theory, like in other mathematics courses.

Math 104 is an entirely new class that replaces Math 103. All rumors concerning 103 are now obsolete :) You can understand "matrix theory" as being the same as "linear algebra", but Math 104 will mostly differ from the other class Math 113 in the choice of topics: very roughly speaking, Math 104 will be to "analysis" what Math 113 is to "algebra".

Textbook

The required textbook is Numerical Linear Algebra by L. N. Trefethen and D. Bau III, ed. SIAM (1997). It will NOT be available at the bookstore. Instead, the plan is to order it online with a decent discount from the editor. I recommend going through the following steps:

  • Become a student member of the Society for Industrial and Applied Mathematics (SIAM) by signing up here. It's free and as a perk you will receive the 8-page newsjournal "SIAM news" once every 2 months.

  • With student membership you have a 30 percent discount on all SIAM books, including the class textbook. Order the book here and don't forget to scroll down choose "SIAM member price" over "List price" at the bottom of the page. Make sure you specify "Member price Math 104 Stanford" in the Special Instruction box before submitting your order. If one of the steps of ordering online poses an insurmountable difficulty to you, contact the teaching staff for help.

  • If you wish to purchase the book elsewhere, or if you wish to group orders among yourselves, that is fine. One copy of the book will be on reserve at the Math/CS library.

    The lecture may be inspired by material from other books, but typeset notes will be provided everytime this happens. One of these books is Introduction to Linear Algebra by G. Strang. It's a great book, but consider it an optional purchase in the scope of the course.

    Link to the class notes: December 1 draft. Older versions: 10/14, 10/06, 09/24.

    Link to the first few lectures in Trefethen's book: here.

    Prerequisites

    Math 51, and either Math 52 or Math 53. Alternatively, familiarity with the following notions:

  • Vector operations: dot product, cross product;
  • Matrix operations: matrix-matrix multiplication, matrix-vector multiplication;
  • Partial derivatives and the chain rule of vector calculus;
  • Definition of eigenvalue and eigenvector;
  • 3-by-3 determinants.
  • No knowledge of computer programming is necessary. There will be no programming assignment.

    Who, when and where

    Instructor

    Laurent Demanet
    Contact info

    Lecture: MWF 10:00a - 10:50a
    Room 380-F

    Office hours: MWF 11:00a - 12:00p
    or by appointment
    Room 380-382J

    Course assistant

    Dmitriy Ivanov



    Office hours: MW 1p-2p and Th 3p-4p
    Room 380-U1

    The first day of class is Monday September 22. The drop deadline is October 19.

    Exams and homework

    There will be weekly homework, one midterm exam and one final exam. Grading: homework 25%, midterm 25%, final 50%. The lowest grade on the homework will be dropped.

    Exams

    The midterm exam will take place in class from 10:00a to 10:50a, on Wednesday October 15 (room 380-F). It is an open-book, open-notes exam. In accordance with University scheduling, the final exam will be on Friday December 12 from 8:30a to 11:30a, room 380-F.

    Homework

    Assignments are usually posted each Thursday and due to the CA the following Thursday at 5PM (see exact dates on the right when in doubt). No late copies will be accepted. It is okay to discuss the homework with others, but you need to work by yourself on the final copy you'll turn in.

    Principal 
directions as singular vectors


    Online course evaluation

    We kindly ask that you complete an online course evaluation at the end of the term, via Axess. Your opinion is very important to us!

    Further help and advice

  • Suggested exercise on commuting matrices
  • Confused about the material? Your first resource should be the office hours offered by the course assistant and the instructor. Office hours are also a good time if you wish to give us feedback on the class.
  • Please write neat and complete solutions to the problem sets. "Neat" means well structured, not only esthetically, but also logically. "Complete" means that the grader will need to see a sufficient amount of explanations and details to give you full credit, even if the question only asks for a numerical answer.

  • Thanks to xkcd