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Re: matrix algebra

• To: mathgroup at smc.vnet.net
• Subject: [mg3700] Re: matrix algebra
• From: Harald Berndt <haraldb at nature.berkeley.edu>
• Date: Mon, 8 Apr 1996 02:06:06 -0400
• Organization: University of California Forest Prodcts Lab
• Sender: owner-wri-mathgroup at wolfram.com

Juan Garcia Velo wrote:
> 
> Does anybody know of a package of functions and operators that can deal
> with partitioned matrices? Example:
> mat_a = [ a b ]    mat_b = [ d c ]
>         [ c d ]            [ b a ]
> where a, b, c, d are matrices (although not necessarily defined) of
> appropriate dimensions. Then I can do MULT[mat_a,mat_b] and get
> mat_c = [ a d + b b    a c + b a ]
>         [ c d + d b    c c + d a ]
> without any attempt of changing the order in the products defining the
> elements of mat_c, because they are matrices, obviously.
> 
> Juan

Would it be sufficient for your needs to just use the generalization 
of the Dot product, Inner[f, list1, list2, g], with f=Dot and g=Plus? 
You won't have any dimension checking etc. and will need to write out 
explicitly what you want each time, but it will do what you want, I 
believe.
-- 
______________________________________________________________________
Harald Berndt,                                University of California
Research Specialist                         Forest Products Laboratory

Phone:	510-215-4224                                FAX:			510-215-4299

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