1. Not finding help here? Sign up for a free 30min 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!

Linear Algebra: Block System

  1. Jan 30, 2012 #1
    1. See the following picture:
    http://imageshack.us/photo/my-images/715/math5610.jpg/

    Essentially what I'm trying to do is solve a linear block system.
    I have got to the point where I now need to "add multiples of the top rows to clear out C."
    Now, I'm sure this is the easy part as I've already had to make a Matlab program to solve a tridiagonal system, but I just can't figure out how I essentially eliminate C.

    Known: I (identity), E, x1,b3,C,D,x2,b2.



    Like I said, I'm sure I'm making this easy step very difficult, but I don't know where to proceed :/
     
  2. jcsd
  3. Jan 31, 2012 #2
    Just a bump. I'm sure this is easy LA I can't figure out.
     
  4. Jan 31, 2012 #3
    Turns out the image isn't showing, sorry for another post:
    rl9ksn.jpg
     
  5. Jan 31, 2012 #4

    hotvette

    User Avatar
    Homework Helper

    I think all they are saying is that you can use Gauss elimination to systematically zero out the elements of C. For example, let's say the upper left element of C is c1. Multiply the top row of the matrix by -c1 and add it to the row containing c1. Now the upper left corner of C is zero. Next pick the proper row in the upper part of the matrix to zero out the next non-zero term of C, and so on until all elements of C are zero. It might help to write out a small made up problem (e.g. each sub-matrix is a 2x2) and work through the steps by hand.
     
  6. Jan 31, 2012 #5
    Ya, that's what I was figuring, but I was hoping there would be an easier way to do it (I'm programming it in Matlab).
    Obviously, a double loop will work and get the job done, but was looking to see if there was a slicker way to do it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Linear Algebra: Block System
Loading...