Re: Common factors in a list

*To*: mathgroup at smc.vnet.net*Subject*: [mg58338] Re: [mg58327] Common factors in a list*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Tue, 28 Jun 2005 21:56:38 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

Mathematica will just undo the operation since the multiplication is automatic expr1=a*{x,y,z} {a x,a y,a z} You can use a dummy operator such as CircleTimes expr2=expr1/.{a_*x_,a_*y_,a_*z_}:> CircleTimes[a,{x,y,z}] a ? {x, y, z} And clear it with expr2/.CircleTimes:>Times {a x,a y,a z} Bob Hanlon > > From: "John Reed" <nospamjreed at alum.mit.edu> To: mathgroup at smc.vnet.net > Date: 2005/06/28 Tue AM 05:13:27 EDT > Subject: [mg58338] [mg58327] Common factors in a list > > I'm working with a list (vector) that's composed of functions such as > complex exponentials and Bessel functions. Some of the functions are common > to each element of the list. I'm trying to find a way to do the following: > > {a x, a y, a z}-> a *{x, y, z} > > In this expression, a, x, y, z are polynomials, exponentials and/or Bessel > functions. > > So far I haven't had any luck with this. Does anyone have a simple > solution? > > John Reed > >