[datatable-help] data.table crashes R session

[Christoph Jäckel]

Note: I posted this on Nabble before, but it keeps telling me that it has
not been accepted by the mailing list. So this might be a duplicate.

Hi together,

I recently encountered severe problems with R (see my post on stackoverflow
here:
http://stackoverflow.com/questions/8616862/r-terminates-with-error-message-this-application-has-requested-the-runtime-to-t).
Spending the whole day digging further into the problem, I was able to
produce rather minimal code that crashes my RStudio session. I confirmed
this on two different machines (see details at the end).  If I run this
code in my Linux Terminal, I get the following error:

 *** caught segfault ***
address (nil), cause 'unknown'

Traceback:
 1: as.data.frame.Date(x[[i]], optional = TRUE)
 2: as.data.frame(x[[i]], optional = TRUE)
 3: data.frame(ID = rep(1:100, each = n/100), intTime = rep(1:(n/100),
times = 100), FYE = lDate1 + 1:n)

So it looks like a similar problem  to caneff's problem:
http://r.789695.n4.nabble.com/Random-segfaults-td4195472i20.html

So my two questions are:
1. Can you confirm this? (Sometimes, I have to run the code a couple of
times to get R to crash)
2. What is the cause? (Interestingly, I need to add the line DT[,
reportDate := NA] to get the code breaking, although this line seems
completely irrelevant for the further computations. For me, R closes when
the last line is run.)

Rather minimal code:

get_diff_month <- function(actualDate, baseDate) {

  #Because data.table also has a month function
  return(month(actualDate) - month(baseDate) + 12*(year(actualDate) -
year(baseDate)))
}
library(data.table)

n <- 100000
lDate1 <- as.Date("1jan1900", "%d%b%Y")#dmy("1Jan1900")
lDate2 <- as.Date("1jan1901", "%d%b%Y")#dmy("1Jan1901")
df <- data.frame(ID = rep(1:100, each=n/100),
                 intTime = rep(1:(n/100), times=100),
                 FYE=lDate1 + 1:n)
DT <- as.data.table(df)
DT[rbinom(n, size=1, prob=0.05)==1, FYE:=NA]
DT[, reportDate := NA] #Bad line: comment it out and nothing breaks!
DT[, intFYE      := get_diff_month(FYE, as.Date("1jan1900", "%d%b%Y"))]
intDT <- DT[ , list(FYE, intTime, ID)]
newDates <- intDT[, intTime] - 1
intDT[, intTime := newDates]
#Set keys
key(DT)    <- c("ID", "intTime")
key(intDT) <- c("ID", "intTime")
DT <- merge(DT, intDT, all.x=TRUE)
DT[, intFYE_Next := get_diff_month(FYE.y, as.Date("1jan1900", "%d%b%Y"))]

sessionInfo() 1:

R version 2.13.2 (2011-09-30)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=C

 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C
           LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] data.table_1.7.7

loaded via a namespace (and not attached):
[1] tools_2.13.2

sessionInfo() 2:


R version 2.14.0 (2011-10-31)
Platform: x86_64-pc-mingw32/x64 (64-bit)

locale:
[1] C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] data.table_1.7.7

loaded via a namespace (and not attached):
[1] tools_2.14.0

Thanks Christoph

-- 
--------------------------------------------------------------------------------------------------------------------------------------------------------------------

Christoph Jäckel (Dipl.-Kfm.)

--------------------------------------------------------------------------------------------------------------------------------------------------------------------

Research Assistant

Chair for Financial Management and Capital Markets | Lehrstuhl für
Finanzmanagement und Kapitalmärkte

TUM School of Management | Technische Universität München

Arcisstr. 21 | D-80333 München | Germany

Mailto: christoph.jaeckel at wi.tum.de | Web: www.fm.wi.tum.de

Phone: +49 89 289 25487 | Fax: +49 89 289 25488



Head of Chair:

Univ.-Prof. Dr. Christoph Kaserer

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