1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Simple Linear Algebra question

  1. Feb 9, 2008 #1
    I have to do a LDL[tex]^{T}[/tex] transform of a symmetrical matrix:

    [2 -1 0]
    [-1 2 -1]
    [0 -1 2]

    And, I'm just wondering if I have to do a row exchange, or something. I can't remember if the L matrix has to have the form

    [x 0 0]
    [x x 0]
    [x x x]

    where the x's are nonzero numbers.

    Basically, I'm asking if that 0 in the lower left hand corner is all right, and if I only need to eliminate the -1 at positions 2,3 and 1,2

    Thank you.
  2. jcsd
  3. Feb 9, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Yes, L is, by definition, a "Lower Triangular" matrix. It must have only 0s above ther diagonal. It is not required that all other numbers not be 0.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Simple Linear Algebra question