Results 1 to 2 of 2

Math Help - How to find Inverse of a Non-Square Matrix...

  1. #1
    Newbie
    Joined
    Dec 2009
    Posts
    1

    How to find Inverse of a Non-Square Matrix...

    Hi All,

    While doing a DePrecoder for LTE_MIMO, i need to do matrix division. Since matrix division is not possible, i tried to take the inverse of the matrix and multiply it. If it is a square matrix then the above condition will work fine. how to do that for a Non_Square Matrix....??

    Ex...,

    a = [1 2 3; 4 5 6];
    b = [4 5; 2 3; 5 6];

    c = a * b;

    Now if i want to find matrix b means....

    b = c * (1/a) = c * inv(a);

    Here inv(c) will not work coz it is not a square matrix. Please help me in finding it.

    NOTE : PseudoInverse - pinv() in MATLAB is also not working.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,394
    Thanks
    1845
    Quote Originally Posted by rajez79 View Post
    Hi All,

    While doing a DePrecoder for LTE_MIMO, i need to do matrix division. Since matrix division is not possible, i tried to take the inverse of the matrix and multiply it. If it is a square matrix then the above condition will work fine. how to do that for a Non_Square Matrix....??

    Ex...,

    a = [1 2 3; 4 5 6];
    b = [4 5; 2 3; 5 6];
    a= \begin{bmatrix}1 & 2 & 3 \\ 4 & 5 & 6\end{bmatrix}
    b= \begin{bmatrix}4 &  2 & 3\\ 5 & 6\end{bmatrix}
    c = a * b;

    Now if i want to find matrix b means....

    b = c * (1/a) = c * inv(a);

    Here inv(c) will not work coz it is not a square matrix. Please help me in finding it.

    NOTE : PseudoInverse - pinv() in MATLAB is also not working.[/QUOTE]
    A non-square matrix does NOT have an inverse, of course. Your matrix a, above, maps R3 into R2 so obviously, its null space is non-trivial. In this case, its null space is the one dimensional subspace spanned by <1, -2, 1>. That also means that, given a two by two matrix c, there exist an infinite number of two by three matrices, b, such that ab= c.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: May 25th 2010, 04:55 AM
  2. Find the inverse of a matrix
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: December 29th 2009, 01:18 AM
  3. Find the square root of a 3x3 matrix
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: December 6th 2009, 06:30 AM
  4. Replies: 1
    Last Post: February 10th 2009, 02:54 PM
  5. How to find inverse of matrix?
    Posted in the Calculators Forum
    Replies: 4
    Last Post: October 26th 2008, 10:01 AM

Search Tags


/mathhelpforum @mathhelpforum