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RE: How to do symbolic matrix manipulations

• To: mathgroup at smc.vnet.net
• Subject: [mg92289] RE: [mg92276] How to do symbolic matrix manipulations
• From: "Jose Luis Gomez" <jose.luis.gomez at itesm.mx>
• Date: Sat, 27 Sep 2008 06:46:56 -0400 (EDT)
• References: <200809261023.GAA09890@smc.vnet.net>

In Mathematica the asterisk is used for commutative multiplication, for the
noncommutative matrix multiplication you must use a dot: a.b 

See this link:
http://reference.wolfram.com/mathematica/ref/Dot.html 

Be sure to check also MatrixPower, or you will also have problems with
powers of matrices:
http://reference.wolfram.com/mathematica/ref/MatrixPower.html

Hope that helps

Jose
Mexico

-----Mensaje original-----
De: Peng Yu [mailto:pengyu.ut at gmail.com] 
Enviado el: Viernes, 26 de Septiembre de 2008 05:24
Para: mathgroup at smc.vnet.net
Asunto: [mg92276] How to do symbolic matrix manipulations

Hi,

Suppose I have matrices a and b, which does not have any value yet.

If I write b * a, mathematica would give me "a b". I'm wondering how to make
it know that a and b are matrices, so that it would give me "b a" rather
than "a b".

Thanks,
Peng

• References:
  • How to do symbolic matrix manipulations
    • From: "Peng Yu" <pengyu.ut@gmail.com>