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About LU factorization
06-05-2015, 09:00 PM
Post: #24
RE: About LU factorization
(06-05-2015 08:38 PM)Claudio L. Wrote:  To get the permutation matrix, simply create an NxN matrix with all zeros, and for each row, take a number off the list, and put a 1 in the corresponding column.
For example:
[ 1 , 3 , 2 ] --> Put a 1 in the 1st column on row 1, on row 2 put it in the 3rd column, and on the 3rd row put it in the 2nd column.
You'll get [[ 1 0 0 ] [0 0 1] [0 1 0]], which is what you are looking for.

thank you Claudio!

something like this?
Code:

EXPORT permMatrix(lst)
// given a permutation list (like {1,3,2}) and the matrix dimension, returns a permutation matrix
BEGIN
local j, k, mat, dimen;
dimen:= length(lst);
mat:= MAKEMAT(0, dimen, dimen);
FOR j FROM 1 TO dimen DO
mat(j,lst(j)):= 1;
END; // for
RETURN mat;
END;

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
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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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