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MathGroup Archive 2005

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Re: matrices in matrices

  • To: mathgroup at smc.vnet.net
  • Subject: [mg53892] Re: [mg53868] matrices in matrices
  • From: Chris Chiasson <chris.chiasson at gmail.com>
  • Date: Wed, 2 Feb 2005 06:25:55 -0500 (EST)
  • References: <200502010908.EAA15017@smc.vnet.net>
  • Reply-to: Chris Chiasson <chris.chiasson at gmail.com>
  • Sender: owner-wri-mathgroup at wolfram.com

Dr. Mario Encinosa,

Try looking at the matrix manipulation package, it has specific
functions for manipulating pieces of matrices. Here is some code from
the help browser that probably does something similar to what you
want.

<< LinearAlgebra`MatrixManipulation`
a = {{a11, a12}, {a21, a22}}; MatrixForm[a]
b = {{b11, b12}, {b21, b22}}; MatrixForm[b]
BlockMatrix[{{a, b}, {b, {{0, 0}, {0, 0}}}}]//MatrixForm

On a semi-related note, I find that one of the most difficult parts of
using Mathematica is figuring out where to look for information on
Mathematica's implementation of whatever I am trying to do. This is
one reason I am excited about the new Mathematica Wiki
(http://www.mma-users.org/). Wikis seem to be easier for search
engines to "digest" than archives of the MathGroup or user forums.

Regards,


On Tue, 1 Feb 2005 04:08:18 -0500 (EST), mario encinosa
<mencinosa at comcast.net> wrote:
> i am hoping some of the experts can help me out. i calculate a bunch
> (144 to be precise) of 5 x 5 matrices to be used in an
> eigenvalue/eigenvector calculation in a full 60 x 60 matrix. i cannot
> seem to build the 60 x 60 in a way usable by Eigenvalues and
> Eigenvectors because when I try things like
> 
> mat = {{M11, M12...},  ...}
> 
> with or without Flatten, it leaves the matrix brackets intact. Any
> help would be greatly appreciated!
> 
> Dr. Mario Encinosa
> Associate Professor of Physics
> 205 Jones Hall
> 850-599-8461
> 
> 


-- 
Chris Chiasson
Kettering University
Mechanical Engineering
Graduate Student
1 810 265 3161


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