Re: Finding length in recursive definition?
- To: mathgroup at smc.vnet.net
- Subject: [mg60887] Re: [mg60877] Finding length in recursive definition?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 2 Oct 2005 01:54:39 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
Clear[f] f=1; f=3; f[n_]:=f[n]=f[n-1]+f[n-2]; f 4 Max[Cases[ReleaseHold[(First/@DownValues[f])/. HoldPattern[f[n_]]:>n],_Integer]] 3 or more simply Length[DownValues[f]]-1 3 Bob Hanlon > > From: "Jose Reckoner" <reckoner at gmail.com> To: mathgroup at smc.vnet.net > Date: 2005/10/01 Sat AM 02:55:52 EDT > Subject: [mg60887] [mg60877] Finding length in recursive definition? > > I have something like: > f = 1 > f = 3 > f[n_] := f[n] = f[n - 1] + f[n - 2] > > and in the course of work, f[n] gets evaluated an unknown number of > times resulting in > > >> ?f > f = 1 > f = 3 > f = 4 > f[n_] := f[n] = f[n - 1] + f[n - 2] > > I want to figure out the greatest integer n such that f[n] has already > been computed and is stored. In this case, it is 3. > > How can I do this? > > Thanks! > > Jose > >