[Date Index] [Thread Index] [Author Index]

Re: Symbolic Derivatives of Unspecified Functions

• To: mathgroup at smc.vnet.net
• Subject: [mg70732] Re: Symbolic Derivatives of Unspecified Functions
• From: David Bailey <dave at Remove_Thisdbailey.co.uk>
• Date: Wed, 25 Oct 2006 01:39:58 -0400 (EDT)
• References: <ehf1mp$5e9$1@smc.vnet.net> <ehhqlj$7cm$1@smc.vnet.net> <ehkc7f$hjf$1@smc.vnet.net>

Hello,

A definition such as r[qi_,qj_]:=r[qi,qj] (or the equivalent using =) is 
meaningless - it simply defines r in terms of itself - this sends 
Mathematica into a spin, which produces your iteration limit error. I am 
sorry if you thought I was suggesting this - I was merely quoting a bit 
of your original message!

The crucial thing to understand is that you can differentiate a function 
(or use it in other ways) without providing any definition at all - this 
is the appropriate thing to do.

David Bailey
http://www.dbaileyconsultancy.co.uk