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

  • To: mathgroup at smc.vnet.net
  • Subject: [mg94135] Re: Do I have to worry about "Left" division for matrices?
  • From: dh <dh at metrohm.com>
  • Date: Fri, 5 Dec 2008 05:34:44 -0500 (EST)
  • References: <gh8hoh$r4h$1@smc.vnet.net>


Hi,

  The star operator "*" works element by elemet. The operator you want 

is: Dot ".". It binds the leftmost index of the left operand and the 

rightmost index of the right operand.

Therefore you would write:

Inverse[A].b for left division and

b.Inverse[A] for right division.

hope this helps, Daniel





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.

> 




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