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Re: FindRoot and replacement rule

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123924] Re: FindRoot and replacement rule
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Fri, 30 Dec 2011 07:08:05 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201112290751.CAA21070@smc.vnet.net>
  • Reply-to: drmajorbob at yahoo.com

a) In a multivariable problem, rules give an explicit correspondence  
between variables and optimum values. Otherwise, you'd have to guess in  
what order solutions are given.

b) Sometimes it isn't possible to predict WHICH variables will have  
values, much less in what order. That's certainly true for Solve, when the  
system is underdetermined.

c) ReplaceAll (/.) and a list of rules provide a simple way of extracting  
the right values for the right variables.

Bobby

On Thu, 29 Dec 2011 01:51:25 -0600, SamTakoy <pavelgrinfeld at gmail.com>  
wrote:

> Hi,
>
> Just wondering why FindRoot and other solvers return substitution
> rules rather than simply a list of solutions. What's the advantage?
>
> Thanks!
>
> Sam
>


-- 
DrMajorBob at yahoo.com



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