Re: Almost symbolic computations (?)
- To: mathgroup at smc.vnet.net
- Subject: [mg90492] Re: Almost symbolic computations (?)
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Thu, 10 Jul 2008 07:32:05 -0400 (EDT)
- Organization: Uni Leipzig
- References: <g54oim$etu$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
Hi, and ax, ay and az should not be functions of your space variables ? For constants the derivative is always 0 Regards Jens Barbara Da Vinci wrote: > Dear MathGroup > > This is an example of the problem > I'm facing. > > The code > > Needs["VectorAnalysis`"]; > Head /@ {ax, ay, az} > A = {ax, ay, az}; > Curl[A] > > returns > > {Symbol, Symbol, Symbol} > {0, 0, 0} > > Instead, I would get the > well known symbolic form > > d_y az - d_z ay > ... > > I have been trying, for > a while, to perform string > manipulations but that, > of course, lays to ashes > the possibility to recognize > > d_y az + d_y az = 2 d_y az > > and so on. > > Any way to get out of it ? > > Kind regards > > > Barbara Da Vinci >