Services & ResourcesWolfram ForumsMathGroup Archive

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

Re: Do I have to worry about "Left" division for matrices?

• To: mathgroup at smc.vnet.net
• Subject: [mg94154] Re: [mg94088] Do I have to worry about "Left" division for matrices?
• From: Daniel Lichtblau <danl at wolfram.com>
• Date: Sat, 6 Dec 2008 06:13:07 -0500 (EST)
• References: <200812041217.HAA27795@smc.vnet.net>

Tyler wrote:
> Hello All:
> 
> I am currently in the process of rewriting some old code into
> Mathematica. One of the things I've come across is the matrix
> operation
> 
> A \ b
> 
> Which is defined as "left division." In other words (if I have this
> right):
> 
> A \ b = inv(A)*b
> 
> and "right division" is
> 
> b / A = b*inv(A)
> 
> I guess my question is, does mathematica make the distinction between
> left and right division, or is this more or less related to the
> algorithm used by the solver (I am using numerical values by the way,
> and not a symbolic solution)?
> 
> Cheers,
> 
> t.

The (preferred) Mathematica equivalents would be LinearSolve[A,b] and 
LinearSolve[Transpose[A],b] respectively.

Mathematica does not support an infix form of this sort of division, so 
the immediate question is moot.

Daniel Lichtblau
Wolfram Research

• References:
  • Do I have to worry about "Left" division for matrices?
    • From: Tyler <hayes.tyler@gmail.com>