Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1997
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1997

[Date Index] [Thread Index] [Author Index]

Search the Archive

MatrixExp[DiagonalMatrix[{1,1,-1,-1}]] & MMA 3.0

  • To: mathgroup at smc.vnet.net
  • Subject: [mg7617] MatrixExp[DiagonalMatrix[{1,1,-1,-1}]] & MMA 3.0
  • From: Robert Prus <robert at fuw.edu.pl>
  • Date: Thu, 19 Jun 1997 15:53:33 -0400 (EDT)
  • Organization: Warsaw University, Physics Department
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

I discovered that MatrixExp[] command in Mathematica 3.0 gives wrong results.

Here are two examples of using MatrixExp[] with two versions of Mathematica
(2.2 and 3.0):


Mathematica 2.2 for SPARC
Copyright 1988-94 Wolfram Research, Inc.
 -- Terminal graphics initialized -- 

In[1]:= MatrixExp[DiagonalMatrix[{1,1}]]

Out[1]= {{E, 0}, {0, E}}

In[2]:= MatrixExp[DiagonalMatrix[{-1,-1}]]

          1          1
Out[2]= {{-, 0}, {0, -}}
          E          E

In[3]:= MatrixExp[DiagonalMatrix[{1,1,-1,-1}]]

                                            1                1
Out[3]= {{E, 0, 0, 0}, {0, E, 0, 0}, {0, 0, -, 0}, {0, 0, 0, -}}
                                            E                E

Mathematica 3.0 for Solaris
Copyright 1988-96 Wolfram Research, Inc.
 -- Terminal graphics initialized -- 

In[1]:= MatrixExp[DiagonalMatrix[{1,1}]]

Out[1]= {{E, 0}, {0, E}}

In[2]:= MatrixExp[DiagonalMatrix[{-1,-1}]]

          1          1
Out[2]= {{-, 0}, {0, -}}
          E          E

In[3]:= MatrixExp[DiagonalMatrix[{1,1,-1,-1}]]

          1                1
Out[3]= {{-, 0, 0, 0}, {0, -, 0, 0}, {0, 0, E, 0}, {0, 0, 0, E}}
          E                E


Mathematica 3.0 gives wrong result for last calculation, i.e.
MatrixExp[DiagonalMatrix[{1,1,-1,-1}]] while MMA 2.2 gives correct result.

Any ideas for solving that problem?

RP

-- 
Robert Prus, robert at fuw.edu.pl
Institute of Theoretical Physics, Warsaw University
Hoza 69, 00-681 Warsaw, Poland
tel./fax (48)(2) 6214397


  • Prev by Date: Re: combinatorics problem
  • Next by Date: Xah's graphs under rotation
  • Previous by thread: FontForm
  • Next by thread: Xah's graphs under rotation