Re: column * row ??
- To: mathgroup at smc.vnet.net
- Subject: [mg28819] Re: column * row ??
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Tue, 15 May 2001 00:58:54 -0400 (EDT)
- References: <9dlcc6$o2p@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
John, We need to make the lists into matrice -- column and row matrices: {{a1},{a2},{a3}}.{{b1,b2}} {{a1 b1,a1 b2},{a2 b1,a2 b2},{a3 b1,a3 b2}} -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565 "J.R. Chaffer" <jrchaff at mcn.net> wrote in message news:9dlcc6$o2p at smc.vnet.net... > 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 >