[26195] in Athena Bugs
maple bug?
daemon@ATHENA.MIT.EDU (Erica H Peterson)
Tue Nov 23 10:48:36 2004
Date: Tue, 23 Nov 2004 10:47:54 -0500 (EST)
From: Erica H Peterson <astronut@mit.edu>
To: bugs@mit.edu
Message-ID: <Pine.LNX.4.58L.0411231038540.6371@amalgam.mit.edu>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: mforbes@mit.edu
Errors-To: bugs-bounces@mit.edu
Hello,
OLC received the following question, which appears to indicate a bug in
Maple:
*********************************************************************
Question:
What is wrong with the following code?
with(LinearAlgebra):
lambda6:=Matrix([[0,0,0],[0,0,1],[0,1,0]]):
lambda8:=Matrix([[1,0,0],[0,1,0],[0,0,-2]]):
Sigma1:=MatrixExponential(I*(theta6*lambda6+theta8*lambda8)):
Sigma2:=MatrixExponential(I*(0*lambda6+theta8*lambda8)):
simplify(subs(theta6=0,Sigma1));
simplify(Sigma2);
-----------------------------------
Both of these final expressions should be the same: in particular, they
should have three non-zero diagonal entries. When executed on the current
version of maple (command line version), the first result is erroneous.
(I have tried this on several platforms with Maple and have found the same
problem.) If you substitute for a non-zero value, then there is no
problem, but at zero something strange happens. I have not made any
assuptions about theta6 (such as it being positive etc.) and so the
resulting expression should be valid (there are no singularities in the
result).
*********************************************************************
Thanks,
Erica
