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About LU factorization
06-04-2015, 12:48 PM (This post was last modified: 06-04-2015 01:11 PM by salvomic.)
Post: #12
RE: About LU factorization
Dale,
I found this:
if I reorder a matrix like the "permutation" vector given by LU() (i.e. [1,3,2] for our matrix) LU() gives the same pivots like my (much imperfect try to write a program to calculate pivots: see here: GaussJordan() ).

In our example (first LU gave [1,3,2]...) I get:
M1:= [[2,1,1], [-2,7,2], [4,-6,0]]
LU(M1) -> {[1,2,3], [[1,0,0], [-1,1,0], [2,-1,1]], [[2,1,1], [0,8,3], [0,0,1]]} (Doolittle; pivots in U: 2,8,1)
my program gives: gaussJordan([[2,1,1], [-2,7,2], [4,-6,0]]) -> [[2,8,1], [[2,1,1], [0,8,3], [0,0,1]]] (by the way REF(M1) -> [[1,0.5,0.5], [0,1,0.25], [0,0,1]])

I would like to understand how to get the result presented by Strange (pivots: 2, -8, 1 and so on)...
(EDIT: The example of Gil Strange is intended for LU factorization without swapping of rows)

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Messages In This Thread
About LU factorization - salvomic - 06-04-2015, 09:10 AM
RE: About LU factorization - Paul Dale - 06-04-2015, 09:18 AM
RE: About LU factorization - salvomic - 06-04-2015, 09:52 AM
RE: About LU factorization - Tugdual - 06-04-2015, 10:15 AM
RE: About LU factorization - Paul Dale - 06-04-2015, 10:22 AM
RE: About LU factorization - Tugdual - 06-04-2015, 10:36 AM
RE: About LU factorization - DrD - 06-04-2015, 10:31 AM
RE: About LU factorization - DrD - 06-04-2015, 10:45 AM
RE: About LU factorization - salvomic - 06-04-2015, 11:06 AM
RE: About LU factorization - DrD - 06-04-2015, 11:30 AM
RE: About LU factorization - salvomic - 06-04-2015, 12:05 PM
RE: About LU factorization - salvomic - 06-04-2015 12:48 PM
RE: About LU factorization - DrD - 06-04-2015, 01:31 PM
RE: About LU factorization - salvomic - 06-04-2015, 01:36 PM
RE: About LU factorization - DrD - 06-04-2015, 02:12 PM
RE: About LU factorization - salvomic - 06-04-2015, 02:19 PM
RE: About LU factorization - DrD - 06-04-2015, 02:19 PM
RE: About LU factorization - salvomic - 06-04-2015, 02:22 PM
RE: About LU factorization - Werner - 06-04-2015, 04:57 PM
RE: About LU factorization - Gerald H - 06-04-2015, 05:10 PM
RE: About LU factorization - salvomic - 06-04-2015, 05:10 PM
RE: About LU factorization - salvomic - 06-05-2015, 08:15 PM
RE: About LU factorization - Claudio L. - 06-05-2015, 08:38 PM
RE: About LU factorization - salvomic - 06-05-2015, 09:00 PM
RE: About LU factorization - Claudio L. - 06-08-2015, 01:12 PM
RE: About LU factorization - salvomic - 06-08-2015, 01:15 PM
RE: About LU factorization - parisse - 06-07-2015, 06:42 PM
RE: About LU factorization - salvomic - 06-07-2015, 07:20 PM



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