Re: simple question

*To*: mathgroup at smc.vnet.net*Subject*: [mg99685] Re: simple question*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Mon, 11 May 2009 06:24:01 -0400 (EDT)*References*: <gu660n$9jh$1@smc.vnet.net>

Hi, thank you for this almost complete example. NestWhile[f,startinglist,UnsameQ[{#1[[1]],#2[[1]]}&,2] may work or not. Regards Jens Francisco Gutierrez wrote: > Dear Sirs: > I have a function whose output is of the form {{a,b,c},{d,e,f},k} > > That is, a list of length 3, of which the first two parts are lists and the last part is a number > > Now, I want to iterate it, with the following termination criterion: stop if the first two parts of the output are identical in two successive runs. > > The intuitive (or naively intuitive if you want) way of attacking the problem, I think, is the following: > > NestWhile[f,startinglist,UnsameQ[{#[[1]],#[[2]]}&,2] > > But it does not work. > > What is the solution? > Fg >