Hi list,
I have the following maxima file with output,
where a double invocation of invert_by_lu results in an error
Regards
Andre
----------- matrix_bug.max ----------------
display2d : false;
M : matrix([1,0,0],[v[[1,0],[0,0]],1,0],[v[[0,1],[0,0]],v[[0,1],[1,0]],1]);
/* works */
Minv : invert(M);
Minvinv : invert(invert(M));
/* doesn't work */
Minv : invert_by_lu(M);
Minvinv : invert_by_lu(invert_by_lu(M));
----------- matrix_bug.max ----------------
----------- matrix_bug.txt ----------------
Maxima 5.24.0 http://maxima.sourceforge.net
using Lisp SBCL 1.0.40-1.fc14
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) batch(matrix_bug.max)
read and interpret file: /home/user/matrix_bug.max
(%i2) display2d : false
(%o2) false
(%i3)
M:matrix([1,0,0],[v[[1,0],[0,0]],1,0],[v[[0,1],[0,0]],v[[0,1],[1,0]],1])
(%o3) matrix([1,0,0],[v[[1,0],[0,0]],1,0],[v[[0,1],[0,0]],v[[0,1],[1,0]],1])
(%i4) Minv:invert(M)
(%o4) matrix([1,0,0],[-v[[1,0],[0,0]],1,0],
[v[[0,1],[1,0]]*v[[1,0],[0,0]]-v[[0,1],[0,0]],-v[[0,1],[1,0]],1])
(%i5) Minvinv:invert(invert(M))
(%o5) matrix([1,0,0],[v[[1,0],[0,0]],1,0],[v[[0,1],[0,0]],v[[0,1],[1,0]],1])
(%i6) Minv:invert_by_lu(M)
(%o6) matrix([1,0,0],[-v[[1,0],[0,0]],1,0],
[v[[0,1],[1,0]]*v[[1,0],[0,0]]-v[[0,1],[0,0]],-v[[0,1],[1,0]],1])
(%i7) Minvinv:invert_by_lu(invert_by_lu(M))
Maxima encountered a Lisp error:
The value NIL is not of type CHARACTER.
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
(%o8) "/home/user/matrix_bug.max"
----------- matrix_bug.txt ----------------
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