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Determinate of a Matrix of any (square) order

  1. Aug 21, 2008 #1
    Hello, I'm new to this site.

    I am trying to write a program that will deal with matrices, my problem is in finding a determinate, it would be easy if I limit the usage to 2x2 and 3x3, for which I already know the algorithms. I think that limiting the usage in that way would limit the usefulness of the program. Is there an "easy to program" algorithm for an nXn matrix? I saw something about getting it to upper triangle and multiplying the diagonal numbers together does this work for all matrices?
  2. jcsd
  3. Aug 21, 2008 #2
    I believe so: http://en.wikipedia.org/wiki/Determinant, you can find this quote:

    If A is a triangular matrix, i.e. A_{i,j} = 0 \, whenever i > j or, alternatively, whenever i < j, then [tex] \det(A) = A_{1,1} A_{2,2} \cdots A_{n,n} [/tex] (the product of the diagonal entries of A).

    But maybe you'll enjoy this paper http://www.axler.net/DwD.pdf :)
  4. Aug 21, 2008 #3
    Thanks. That wikipedia article was kind of confusing, at least for me. OK that means I just need to make the program do Gaussian Elimination, which shouldn't be too hard, I hope.
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