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[Maxima-bugs] [ maxima-Bugs-2020810 ] Bug in inverse matrix inverse operator ^^-1
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From: SourceForge.net <no...@so...> - 2009-12-07 02:20:12
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Bugs item #2020810, was opened at 2008-07-17 17:27 Message generated for change (Comment added) made by sf-robot You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2020810&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core Group: None >Status: Closed Resolution: Works For Me Priority: 5 Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: Bug in inverse matrix inverse operator ^^-1 Initial Comment: ------------------------------------------------------------- Maxima version: 5.15.0 Maxima build date: 17:36 4/20/2008 host type: i686-pc-mingw32 lisp-implementation-type: GNU Common Lisp (GCL) lisp-implementation-version: GCL 2.6.8 ------------------------------------------------------------- The inverse operator can not be calculated with the operator ^^-1 when keepfloat is true. Example: (%i16) keepfloat:true; (%o16) true (%i17) A :matrix([0.1 , 0.1],[0 , 0.1]); [ 0.1 0.1 ] (%o17) [ ] [ 0 0.1 ] (%i18) A^^-1; Singular -- an error. To debug this try debugmode(true); (%i19) The command invert(A) works perfectly. It would be nice to give some information of the method used in the ^^-1 operator too. The documentation of invert says it uses the adjoint method, and that a different method is used by ^^-1. However, the documentation doesn't give any clue on how the later works. ---------------------------------------------------------------------- >Comment By: SourceForge Robot (sf-robot) Date: 2009-12-07 02:20 Message: This Tracker item was closed automatically by the system. It was previously set to a Pending status, and the original submitter did not respond within 14 days (the time period specified by the administrator of this Tracker). ---------------------------------------------------------------------- Comment By: Dieter Kaiser (crategus) Date: 2009-11-22 13:11 Message: I think the reported error is no longer present. The Maxima version 5.15.0 is out of date. With Maxima 5.19post we get: (%i22) keepfloat:true$ (%i23) a:matrix([0.1,0.1], [0,0.1])$ (%i24) a^^-1; (%o24) matrix([9.999999999999998,-9.999999999999998],[0,10.0]) (%i25) keepfloat:false; (%o25) false (%i26) a^^-1; (%o26) matrix([10,-10],[0,10]) Settting the status to pending and "works for me". Dieter Kaiser ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=2020810&group_id=4933 |