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

Re: Dot product confusion

• To: mathgroup at smc.vnet.net
• Subject: [mg109942] Re: Dot product confusion
• From: Alois Steindl <Alois.Steindl at tuwien.ac.at>
• Date: Wed, 26 May 2010 07:07:03 -0400 (EDT)
• References: <htg90l$k7h$1@smc.vnet.net>

Hello,
your assumptions seem to be wrong.
The dot product in Mathematica isn't just "the inner product, but the
matrix product, in your case
ptsa*v or v*ptsa.
In the first case v is considered as column vector, in the second one as
row vector.
Matrix products are rarely abelian.

Alois

-- 
Alois Steindl,                           Tel.: +43 (1) 58801 / 32558      
Inst. for Mechanics and Mechatronics     Fax.: +43 (1) 58801 / 32598
Vienna University of Technology,         A-1040 Wiedner Hauptstr. 8-10