On Sun, Jul 25, 2010 at 1:57 AM, Michael Haenlein <haenl...@escpeurope.eu> wrote: > Dear all, > > I'm working with a code that consists of two parts: In Part 1 I'm generating > a random graph using the igraph library (which represents the relationships > between different nodes) and a vector (which represents a certain > characteristic for each node): > > library(igraph) > g <- watts.strogatz.game(1,100,5,0.05) > z <- rlnorm(100,0,1) > > In Part 2 I'm iteratively changing the elements of z in order to reach a > certain value of a certain target variable. I'm doing this using a while > statement: > > while (target_variable < threshold) {## adapt z} > > The problem is that in some rare cases this iterative procedure can take > very long (a couple of million of iterations), depending on the specific > structure of the graph generated in Part 1. I therefore would like to change > Part 2 of my code in the sense that once a certain threshold number of > iterations has been achieved, the iterative process in Part 2 stops and goes > back to Part 1 to generate a new graph structure. So my idea is as follows: > > - Run Part 1 and generate g and z > - Run Part 2 and iteratively modify z to maximize the target variable > - If Part 2 can be obtained in less than X steps, then go to Part 3 > - If Part 2 takes more than X steps then go back to Part 1 and start again > > I think that R does not have a function like "go-to" or "go-back". > > Does anybody know of a convenient way of doing this? > > Thanks very much for your help, >
goto's can be replaced with loops. In this case create a double loop such that the outer loop does not repeat if the inner loop finished due to reaching the target: target_variable <- -Inf while(target_variable < threshold) { ... iter <- 0 while(target_variable < threshold && iter < max_iter) { ... update iter and target_variable ... } } ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.