

Matrix Help
Name: Unknown
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993
Question:
I am using Lotus 123 for Windows and want to calculate the
determinant of a matrix? Has anyone ever written a macro or can help in
setting one up?
Replies:
No, I have never written a Lotus 123 macro for that purpose, but
I have calculated a few determinants numerically in my day. The simplest way
I know of is through LU decomposition. Suppose we want the determinant of a
matrix X. If we can somehow decompose the matrix into the product of two
matrices, i.e., X = L * U, and do it in such a way that L is "lower
triangular" (all nonzero elements on the diagonal and below) and U is "upper
triangular" (all nonzero elements on the diagonal and above), then we can use
L and U to get the determinant. This whole procedure is described in detail
in a book called: Numerical Recipes by W.H. Press, B.P. Flannery, S.A.
Teukolsky, and W.T. Vetterling (Cambridge Press, Cambridge, 1986). It should
be in the library of your local university/college. Hope this has been
helpful.
Topper
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Update: June 2012

