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Re: symbolic matrix manipulation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg96087] Re: symbolic matrix manipulation
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Wed, 4 Feb 2009 05:22:34 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <gm99t7$70$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

Unprotect[Dot]
Dot[\[DoubleStruckOne], a_] := a
Dot[0, a_] := 0
Dot[a, b] := \[DoubleStruckOne] + b.a
Dot[q_Plus, r_] := Dot[#, r] & /@ q
Dot[q_, r_Plus] := Dot[q, #] & /@ r
Protect[Dot]

and

a.b.b.a

gives

2 b.a + b.b.a.a

Regards
   Jens


ashwin.tulapurkar at gmail.com wrote:
> Hi,
> I am trying to simplify the following matrix expression:
> a.b.b.a with the rule: replace a.b by (b.a+1). So I expect the final
> output to be
> a.b.b.a --> (b.a+1).b.a --> b.a.b.a+b.a --> b.(b.a+1).a+b.a -->
> b.b.a.a + 2 b.a
> 
> Can you tell me how to do this?
> 
> Thanks.
> -Ashwin
> 


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