Re: "Quick and dirty" Solve[]
- To: mathgroup at smc.vnet.net
- Subject: [mg108575] Re: "Quick and dirty" Solve[]
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Wed, 24 Mar 2010 04:41:17 -0500 (EST)
On 3/23/10 at 4:24 AM, guerom00 at gmail.com (guerom00) wrote: >In order to found an upper bound for a numerical integration, I >would like to "solve" something like Solve[f[x]<1*^-10,x] but in a >quick and dirty way; let me explain : - dirty, in the sense that I >would be happy to find an x for which f[x] is say between 1*^-9 and >1*^-11 or so - quick in the sense that one evaluation of f[x] takes >some time; the goal would be to find x by evaluating f[x] as fewer >time as possible >Any idea how to do that ? There are several possible ways to approach such a problem. But to make good suggestions, I really need to know something about your f[x]. A couple of possibilities. Plot f[x] over a suitable range. Find a functions h such that f[x]<h[x] over the appropriate range that is easier to evaluate. A useful function h would not be much different than f and would have similar limiting behavior.