ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 04 May 2015 17:05:12 +0200LU decomposition for a matrixhttps://ask.sagemath.org/question/26713/lu-decomposition-for-a-matrix/ There is an inconsistency in the use of the LU decomposition of a matrix. If matrix A is declared in the RDF ring then P, L, U = A.LU () provides PA = LU but if A is declared in the RR ring (or QQ, ZZ,...) then A = PLU. Therefore in a case P is P.transpose () on the other.Mon, 04 May 2015 15:59:21 +0200https://ask.sagemath.org/question/26713/lu-decomposition-for-a-matrix/Answer by tmonteil for <p>There is an inconsistency in the use of the LU decomposition of a matrix. If matrix A is declared in the RDF ring then P, L, U = A.LU () provides PA = LU but if A is declared in the RR ring (or QQ, ZZ,...) then A = PLU. Therefore in a case P is P.transpose () on the other.</p>
https://ask.sagemath.org/question/26713/lu-decomposition-for-a-matrix/?answer=26714#post-id-26714While this is correctly documented (hence not a bug), i agree that there is some inconsistency here. Thanks for reporting, it is now [trac ticket 18365](http://trac.sagemath.org/ticket/18365).
Mon, 04 May 2015 17:05:12 +0200https://ask.sagemath.org/question/26713/lu-decomposition-for-a-matrix/?answer=26714#post-id-26714