MathGroup Archive 2004

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

Search the Archive

Re: Matrix Dot Product

Will this work for you ?

Total[Flatten[Inner[Times, A,
     B, Plus]]]


On Nov 13, 2004, at 4:40 AM, MacDonald, Calum ((MAT)) wrote:

> Hi
> I was wondering if someone could please help me with a command for
> calculating the dot product of two (NxN) matrices.
> For example, for  two (2x2) matrices, A and B, we define the dot 
> product
> as:
> A(1,1)*B(1,1) + A(2,1)*B(2,1) + A(1,2)*B(1,2) + A(2,2)*B(2,2)
> i.e. we multiply corresponding entries of the matrices and sum these
> values.
> It is easy to write this in a loop but for large matrices the
> calculation is rather slow.
> Is there a Mathematica function that I can call that will allow me to 
> do
> this faster?
> Thanks
> Calum
Trying to argue with a politician is like lifting up the head of a 
(S. Lem: His Master Voice)

  • Prev by Date: Re: Challenge: Fastest method to convert positive integers to 1 in a long list
  • Next by Date: Re: Re: 64 bit cpu and Mathematica on windows.
  • Previous by thread: Re: Matrix Dot Product
  • Next by thread: Re: Matrix Dot Product