Re: NMinimize inconsistencies

*To*: mathgroup at smc.vnet.net*Subject*: [mg51306] Re: [mg51293] NMinimize inconsistencies*From*: "Janos D. Pinter" <jdpinter at hfx.eastlink.ca>*Date*: Thu, 14 Oct 2004 06:35:29 -0400 (EDT)*References*: <200410120558.BAA19272@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Skirmantas, as a general rule, you have to specify closed sets for defining the feasible region in any continuous optimization problem (think of minimizing x on 0<x<1). Regards, Janos Pinter At 02:58 AM 10/12/2004, Skirmantas wrote: >I'm puzzled by some inconsistencies of NMinimize. >Namely, >NMinimize[{ Log[( C + P*m - b*P*m)/( C + P*m - a*P*m)]/(a - b), 105 < >C < 315&&2000 < P < 4000&&0 < a < 1 &&0 < b < 1 &&a < b &&0 < m < 5}, >{{C, 105, 315}, {P, 2000,4000}, {a, 0, 1}, {b, 0, 1}, {m, 0, 5}}, >Method -> "NelderMead"] >converges to 0 on a computer running Mathematica 5.0.0. and complains >about 1/0 infinities on a computer running Mathematica 5.0.1. In >Mathematica 5.0.1., changing a<b to a>b still leads to 1/0 infinities >(why?) but then changing a>b to a!=b converges to a solution that is, >amazingly, a>b. Why does NMinimize keep running into 1/0 infinities if >I demand that a>b but not if a!=b? Are there any differences in the >NMinimize implementation in Mathematica 5.0.0. and Mathematica 5.0.1.? >Any help would be appreciated. >Skirmantas

**References**:**NMinimize inconsistencies***From:*skirmantas.janusonis@yale.edu (Skirmantas)