Re: Searching for embedded zeros in list

*To*: mathgroup at smc.vnet.net*Subject*: [mg32147] Re: Searching for embedded zeros in list*From*: Erich Neuwirth <erich.neuwirth at univie.ac.at>*Date*: Sat, 29 Dec 2001 18:00:25 -0500 (EST)*References*: <a0jlsc$31m$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

how about: cut off leading and trailing zeros, and them multiply the remains. if the product is 0, there are embedded zeros, otherwise not. "Coleman, Mark" wrote: > > Greetings, > > Can anyone suggest an efficient/elegant way of checking a list for > 'embedded' zeros. By embedded I mean the occurence of one or more zeros > between two non-zero elements (note: zeros at the ends of the list are > not relevant). For instance, the following lists all contain embedded > zeros: > > a={0.98,0.87,0.0,0.5,0.25} > b={0.9,0.0,0.0,0.0,0.0,0.0,0.05} > c={0.75,0.42,0.10,0.0,0.03} > > while this list does not d={0.0,0.90,0.75,0.42,0.25,0.0} > > By way of background, I am working on a problem involving estimating > generators for Markov transition matrices. One condition that ensures > that a generator *does not* exist is the presence of inaccessible states > in any row of the matrix. Thus one need only find a single occurance of > an inaccessible state to show that a generator does not exist. Hence the > code need only locate one such state, not all of them. > > The Mathematica code I've written for this problem does work, but it is hardly > "elegant". > > Any help would be much appreciated! > > Best regards, > > -Mark -- Erich Neuwirth, Computer Supported Didactics Working Group Visit our SunSITE at http://sunsite.univie.ac.at Phone: +43-1-4277-38624 Fax: +43-1-4277-9386