#1682 echelon problem

closed
nobody
Lisp Core (472)
5
2009-07-22
2009-06-02
Anonymous
No

Maxima version: 5.18.1
Maxima build date: 20:57 4/19/2009
host type: i686-pc-mingw32
lisp-implementation-type: GNU Common Lisp (GCL)
lisp-implementation-version: GCL 2.6.8

I typed in the following commands in Maxima:

(%i1) A:matrix([1,2,2,b1],[2,2,3,b2],[3,4,5,b3]);
[ 1 2 2 b1 ]
[ ]
(%o1) [ 2 2 3 b2 ]
[ ]
[ 3 4 5 b3 ]
(%i2) echelon(A);
[ 1 2 2 b1 ]
[ ]
[ 1 b2 - 2 b1 ]
(%o2) [ 0 1 - - --------- ]
[ 2 2 ]
[ ]
[ 0 0 0 1 ]
(%i3) algebraic:true;
(%o3) true
(%i4) echelon(A);
[ 1 2 2 b1 ]
[ ]
[ 1 b2 - 2 b1 ]
(%o4) [ 0 1 - - --------- ]
[ 2 2 ]
[ ]
[ 0 0 0 1 ]

But shouldn't the result be:

[ 1 2 2 b1 ]
[ ]
[ 1 b2 - 2 b1 ]
[ 0 1 - - --------- ]
[ 2 2 ]
[ ]
[ 0 0 0 b2 - b3 + b1 ]

Discussion

  • Raymond Toy
    Raymond Toy
    2009-07-07

    • status: open --> pending
     
  • Raymond Toy
    Raymond Toy
    2009-07-07

    The documentation for echelon says the first non-zero element in each row is a one. Maxima is producing that result, and is the same as your "expected" result if the last row is divided by b2-b3+b1.

    Marking as pending/invalid.

    If you disagree with this analysis, please update this report.

     
    • status: pending --> closed
     
  • This Tracker item was closed automatically by the system. It was
    previously set to a Pending status, and the original submitter
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