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MathGroup Archive 2001

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column * row ??

  • To: mathgroup at smc.vnet.net
  • Subject: [mg28791] column * row ??
  • From: "J.R. Chaffer" <jrchaff at mcn.net>
  • Date: Sat, 12 May 2001 20:18:24 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi there,

Can someone tell me a way to mimic the building of
an N x N matrix by multiplying a column vector
on left times a row vector on right ? (both vectors
of length N) - I mean in Mathematica, of course.

i.e, want the result,

(colvec){a1,a2, .. aN} * (rowvec){b1,b2,..bN} =

result is matrix:

{{a1*b1  a1*b2 .....  a1*bN},
 {a2*b1  a2*b2 .....  a2*bN},
  ...     ...          ...  ,
 {aN*b1  aN*b2 .....  aN*bN}}


When I try this in Mathematica all I can figure out
how to produce is the standard dot-product.  If I
try the 'transposed' lists/matrices, I get an error,
even tho the product is defined by basic rules of
matrix multiplication.

Thanks,

John Chaffer


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