This looks like a homework trap set up to catch those trying to use facilities like Rhelp. f = exp(x^2-y+z^(-1))= exp(x^2) * exp(1/z)/exp(y) To maximize clearly needs biggest x (37), smallest y (2) and a z that makes exp(1/z) big -- 0. Except that you'll get Inf etc. Actually, several of the optimization tools in R don't do too badly on this (about half of the routines in optplus (the R-forge version of optimx) get reasobable answers, but there are some oddities depending on starting values. JN
On 07/08/2012 06:00 AM, r-help-request at r-project.org wrote:
Message: 64 Date: Sun, 8 Jul 2012 10:15:34 +0100 From: Raghuraman Ramachandran <optionsraghu at gmail.com> To: R Project Help <r-help at r-project.org> Subject: [R] Help in Optimization of a function Message-ID: <CADgEnDmRbxPoCHSDGghAeVUJxGcbZCAz6Bs99Ty_t=FfEsAXkw at mail.gmail.com> Content-Type: text/plain guRus! I have a function f = exp(x^2-y+(1/z)) Also, x can take values from 1 to 37, y from 2 to 20 and Z from -13 to 51. How can I find the maximum of f using any of the optimization functions please? Is there a way to store the possible values of x, y and Z in a single variable like in a List or in a multi-dimensional array? Thanks for your help Raghu [[alternative HTML version deleted]] ------------------------------