Re: RE: column * row ??
- To: mathgroup at smc.vnet.net
- Subject: [mg28845] Re: [mg28812] RE: [mg28791] column * row ??
- From: Raul Martinez <rmartinez at vrinc.com>
- Date: Tue, 15 May 2001 00:59:19 -0400 (EDT)
- Organization: Vista Research Inc
- References: <200105140533.BAA29490@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
John, David, Here's another Mathematica way to do it. colvec = {a1, a2, a3}; rowvec = {b1, b2, b3}; Outer[Times, colvec, rowvec]. Raul Martinez David Park wrote: > John, > > colvec = {a1, a2, a3}; > rowvec = {b1, b2, b3}; > > Transpose[{colvec}].{rowvec} > {{a1 b1, a1 b2, a1 b3}, {a2 b1, a2 b2, a2 b3}, {a3 b1, a3 b2, a3 b3}} > > But probably the more Mathematica way of doing it would be... > > Outer[#1 #2 &, colvec, rowvec] > {{a1 b1, a1 b2, a1 b3}, {a2 b1, a2 b2, a2 b3}, {a3 b1, a3 b2, a3 b3}} > > David Park > djmp at earthlink.net > http://home.earthlink.net/~djmp/ > > > From: J.R. Chaffer [mailto:jrchaff at mcn.net] To: mathgroup at smc.vnet.net > To: mathgroup 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 > >
- References:
- RE: column * row ??
- From: "David Park" <djmp@earthlink.net>
- RE: column * row ??