Services & ResourcesWolfram ForumsMathGroup Archive

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

Re: Can't multiply non-square matrices.

• To: mathgroup at smc.vnet.net
• Subject: [mg64570] Re: Can't multiply non-square matrices.
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Thu, 23 Feb 2006 00:34:05 -0500 (EST)
• Organization: Uni Leipzig
• References: <dthgr4$n74$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

{a, b}.{{c}, {d}}

??

the usual Times[] * does an element-wise multiply.

Regards

  Jens


"Chris Young" <c1572young at earthlink.net> schrieb 
im Newsbeitrag news:dthgr4$n74$1 at smc.vnet.net...
| Is there a way to multiply non-square matrices? 
E.g., a 3-row by 2-row
| matrix times a 2-row by 1-row matrix should 
yield a 3-row by 1-row
| matrix, if I remember my linear algebra 
correctly.
|
| Instead when I do something like
|
|   (a  b) (c)
|          (d)
|
| I get an error involving "Thread::tdlen":
|
| Thread::tdlen: Objects of unequal length in {{a, 
b}}\{{c}, {d}} cannot be \
| combined.
|
| (The "(c)" and "(d)" above represent a 
2-dimensional column vector,
| with one pair of parenthese around them.)
|
| I entered the line
| << LinearAlgebra`MatrixManipulation`
| but this doesn't seem to help.
|
| Any help appreciated.
|
| Chris Young
| 

• Follow-Ups:
  • Re: Re: Can't multiply non-square matrices.
    • From: Murray Eisenberg <murray@math.umass.edu>