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Re: NDSolve

• To: mathgroup at smc.vnet.net
• Subject: [mg62392] Re: NDSolve
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Wed, 23 Nov 2005 01:12:08 -0500 (EST)
• Organization: Uni Leipzig
• References: <dlkc4b$ppg$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

NDSolve[] can not solve elliptic problems, you 
must use the time dependent
solution and compute the limit t->Infinity

Regards
  Jens

"Uli Wuerfel" <uli.wuerfel at fmf.uni-freiburg.de> 
schrieb im Newsbeitrag 
news:dlkc4b$ppg$1 at smc.vnet.net...
| Hello,
|
| although Mathematica solves my coupled system of 
three partial
| differential equations (depending on one spatial 
variable and time)
| I can unfortunately not get it to solve the 
steady-state version
| of the above equations, i.e. only depending on 
one spatial variable.
| I reduced it to a simple diffusion equation, but 
still it does not work.
| My Input is like:
|
| dcb=0.001;
| rcb=1000;
| gen=5e20;
| ab=2000;
| d=0.001;
|
| sol=nc/.First[NDSolve[
| {0==dcb*nc(2)[x]+gen*Exp[-ab*x]-rcb*(nc-nc0),
| nc[0]==nc0,nc(1)[d]==0},nc,{x,0,d}]]
|
| wherein nc(i)[x] stands for the i-th spatial 
derivative of nc[x].
|
| I don´t understand why Mathematica does not 
accept this.
| Could you please help?
|
| Regards,
| Uli
|