Re: How to do symbolic matrix manipulations
- To: mathgroup at smc.vnet.net
- Subject: [mg92304] Re: How to do symbolic matrix manipulations
- From: Peter Breitfeld <phbrf at t-online.de>
- Date: Sat, 27 Sep 2008 06:49:48 -0400 (EDT)
- References: <gbjmam$3ab$1@smc.vnet.net>
Peng Yu schrieb: > 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 > a*b gives the matrix (a_ij * b_ij) which is the same as (b_ij*a_ij), so a*b=b*a. I think you want to do matrix multiplication, which ist done by a.b or Dot[a,b]. If you enter b.a the result will be b.a not a.b Gruss Peter -- ==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-==-== Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de