Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

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

Search the Archive

Re: expression form

  • To: mathgroup at smc.vnet.net
  • Subject: [mg101004] Re: [mg100997] expression form
  • From: "Matthias Bode" <lvsaba at hotmail.com>
  • Date: Sat, 20 Jun 2009 04:01:37 -0400 (EDT)
  • References: <200906200048.UAA00953@smc.vnet.net>

Hello Mr. Haibo Min:

INPUT:
Clear[a, p]
a = {{a1}, {a2}, {a3}};
p = {{p11, p12, p13}, {p21, p22, p23}, {p31, p32, p33}};
Transpose[a] . p

OUTPUT:
{{a1*p11 + a2*p21 + a3*p31, a1*p12 + a2*p22 + a3*p32, a1*p13 + a2*p23 + 
a3*p33}}

Is this the result you intended?

Best regards,

MATTHIAS BODE
Las Lomas de Aranjuez
COCHABAMBA/BOLIVIA
--------------------------------------------------
From: "Haibo Min" <yshdfeng at gmail.com>
Sent: Saturday, June 20, 2009 12:48 AM
To: <mathgroup at smc.vnet.net>
Subject: [mg101004] [mg100997] expression form

> Hi, I am fairly new to mathematica, and I have a question on the matrix
> multiplication operator.
>
> Suppose a={a1,a2,a3},P={{p11,p12,p13},{p21,p22,p23},{p31,p32,p33}}. I want
> to get the explicit expression of a'Pa, where a' is the transpose of 
> vector
> a. Since there is no "transpose" concept for vector, my expression in
> mathematica is
> a.P.a
> However, it just
> returns 
> {a1,a2,a3}.{{p11,p12,p13},{p21,p22,p23},{p31,p32,p33}}.{a1,a2,a3},
> seems nothing is done about this, why?
> I use mathematica v7.0
>
> Thank you!
>
> Haibo Min
> yshdfeng at gmail.com
>
>
> 


  • Prev by Date: Re: compress lists with mean for equal elements
  • Next by Date: Re: compress lists with mean for equal elements
  • Previous by thread: Re: expression form
  • Next by thread: Re: expression form