About LU factorization
06-04-2015, 05:10 PM (This post was last modified: 06-05-2015 09:52 AM by salvomic.)
Post: #21
 salvomic Senior Member Posts: 1,394 Joined: Jan 2015
RE: About LU factorization
(06-04-2015 04:57 PM)Werner Wrote:  ...
Crout factorisation alternatingly computes a row and a column...
Cheers, Werner

hi Werner,
both methods have goods and issues...
Maybe Parisse and Tim could tell us more about the Prime and LU...

However for matrices operations perhaps it could be better to have also some little commands or helps, like a command to extract pivots, to get cofactors, adjoint, minors, and also factorizations LDU (LDV) and LDLt. As they are missing, I'm trying to make some programs, but for pivots I'm getting these troubles...
Some other calculators have those commands, if I well remember (i.e., TI 89/Voyage had adj / cofactor function)...
For example I use a lot a little program to get minor of a matrix:
Code:
 #cas  matrixminor(m,r,c):= BEGIN   m:= delrows(m,r);   m:= delcols(m,c); END; #end
Simple but useful, it helps to don't use delrows() and delcols() more and more. It's alternative to the subMat() command (syntax: subMat(m, r1, c1, r2,c2), and perhaps more short

I made a program to calculate Cofactor matrix and adjoint matrix (see here)...

Salvo

∫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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