Infinite loop
Some systems (both hardware and software) may have "watchdog" timers; I was just using it to illustrate a point as to one way of breaking out. In the case of this loop, it probably run too fast to try and put a timer on it; counting the iterations is good enough. There are some ways of creating timers in R, but I have not used them.
On Tue, Mar 22, 2011 at 1:32 PM, Hosack, Michael <mhosack at state.pa.us> wrote:
Thank you Jim, I was not aware of watchdog timers. R is my first computer language. I searched through the archives and found the function setTimeLimit and applied it with low values for cpu and elapsed time. It provides a way out of the loop which is what I needed. It's not a counter, but I could not find any info. on them in the R archives. Thanks again Mike -----Original Message----- From: jim holtman [mailto:jholtman at gmail.com] Sent: Tuesday, March 22, 2011 1:00 PM To: Hosack, Michael Cc: r-help at R-project.org Subject: Re: [R] Infinite loop The simple thing to do is to put a sanity counter in the 'repeat' statement and if you have been through it a certain number of times, then exit. ?Anytime you have a loop that might run forever, you should have some sanity/watchdog timer on it. On Tue, Mar 22, 2011 at 11:02 AM, Hosack, Michael <mhosack at state.pa.us> wrote:
R experts,
Hello, I am trying to sample a vector 1:40 without replacement such that no element in the new vector
is within 7 units of either of its immediate neighbors. This is part of a larger program I am working
on. The following code works well about 65 % of the time (14/40). The problem I encounter happens when
the last element remaining to be sampled from the vector STRATA is within 7 digits +- of the last element
in the vector s1, at which point an infinite loop occurs. At least that's what I think is happening.
Any help would be greatly appreciated.
Thank you,
Mike
require(IRanges)
STRATA <- 1:40
s1 <- sample(STRATA, 1)
for (i in seq(from = 1, to = 39, by = 1)){
?repeat{
? ?tmp <- sample(STRATA, 1)
? ?if (!any(s1 == tmp) & !any(as.vector(IRanges(s1[length(s1)]-7, s1[length(s1)]+7)) %in% tmp)) break
? ?}
?s1 <- c(s1,tmp)
}
s1
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-- Jim Holtman Data Munger Guru What is the problem that you are trying to solve?
Jim Holtman Data Munger Guru What is the problem that you are trying to solve?