Re: Change of Basis function
- To: mathgroup at smc.vnet.net
- Subject: [mg68999] Re: Change of Basis function
- From: "dennis" <dwangsness at earthlink.net>
- Date: Sat, 26 Aug 2006 02:04:41 -0400 (EDT)
- References: <ecmh90$9iq$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
David Boily wrote: > I would like to know if there is a function capable of giving as output > the representation of a vector in a given basis. For example: > > FunctionX[{1,2,3}, {{1,2,0},{0,1,0},{0,0,1}}] > > (where the first argument is the vector and the second the basis) > > would yield > > {1,0,3} > > and > > FunctionX[f x1 - b x2 + x3 - x2, {x1,x2,x3}] > > would yield > > {f, -b-1, 1} > > I'm more interested in the second case, obviously, because the first one > can be achieved with a simple matrix multiplication. > > David Boily > Center for Intelligent Machines > Mcgill University David, How about Module[vec_,basis_]:=Inverse[Transpose[basis]].vec Dennis