[datatable-help] 'by' on a numeric column produces inconsistent utput

[Arunkumar Srinivasan]

Aha, the issue seems to be with 'uniqlist', not sure why it gives  
> (f__ = data.table:::uniqlist(byval, order=o__)) # 1,3
1,2,3 for you and 1,3 consistently for me. I'll revert this back to `duplist` for now. Not sure how to solve this though. I've tried it so far on 3 machines:


1) OS X 10.8.5 + libvm (gcc)
2) OS X Mavericks + Clang 
3) Debian Weezy + gcc

All of them give consistent output. Man this is such a drag.

Arun


On Thursday, December 19, 2013 at 8:37 AM, Kevin Ushey wrote:

> Hi Arun,
> 
> Here's the output on my machine -- other information missing from
> before; it's with OSX Mavericks, with R and data.table compiled with
> Apple clang.
> 
> ---
> 
> > library(data.table, lib="/Users/kevinushey/Library/R/3.1/library")
> > set.seed(32)
> > n <- 3
> > dt <- data.table(
> > 
> 
> + y=rnorm(n),
> + by=round( rnorm(n), 1)
> + )
> > 
> 
> ## run one
> > byval <- list(by=dt$by)
> > (o__ <- data.table:::fastorder(byval)) # 2,3,1
> > 
> 
> [1] 2 3 1
> > (f__ = data.table:::uniqlist(byval, order=o__)) # 1,3
> 
> [1] 1 2 3
> > (len__ = data.table:::uniqlengths(f__, nrow(dt))) # 2,1
> 
> [1] 1 1 1
> > (firstofeachgroup = o__[f__]) # 2,1
> 
> [1] 2 3 1
> > (origorder = data.table:::iradixorder(firstofeachgroup)) # 2,1
> 
> [1] 3 1 2
> > (f__ = f__[origorder]) # 3,1
> 
> [1] 3 1 2
> > (len__ = len__[origorder]) # 2,1
> 
> [1] 1 1 1
> 
> ## run two
> > (o__ <- data.table:::fastorder(byval)) # 2,3,1
> 
> [1] 1 2 3
> > (f__ = data.table:::uniqlist(byval, order=o__)) # 1,3
> 
> [1] 1 3
> > (len__ = data.table:::uniqlengths(f__, nrow(dt))) # 2,1
> 
> [1] 2 1
> > (firstofeachgroup = o__[f__]) # 2,1
> 
> [1] 1 3
> > (origorder = data.table:::iradixorder(firstofeachgroup)) # 2,1
> 
> [1] 1 2
> > (f__ = f__[origorder]) # 3,1
> 
> [1] 1 3
> > (len__ = len__[origorder]) # 2,1
> 
> [1] 2 1
> 
> On Wed, Dec 18, 2013 at 11:22 PM, Arunkumar Srinivasan
> <aragorn168b at gmail.com (mailto:aragorn168b at gmail.com)> wrote:
> > Not sure how to debug without being able to reproduce. Tried on Mac OS X
> > 10.8.5 and Debian GNU/Linux 7 (wheezy). I don't have access to a windows
> > machine. I consistently gives me this:
> > 
> > > dt[,
> > + list(max=max(y, na.rm=TRUE)),
> > + by=list(by)
> > + ]
> > by max
> > 1: 0.7 0.01464054
> > 2: 0.4 0.87328871
> > > 
> > > dt[,
> > + list(max=max(y, na.rm=TRUE)),
> > + by=list(by)
> > + ]
> > by max
> > 1: 0.7 0.01464054
> > 2: 0.4 0.87328871
> > 
> > Can either of you provide me with the output of these steps in cases where
> > there's an error? I've commented the output I get for each step.
> > 
> > byval <- list(by=dt$by)
> > o__ <- data.table:::fastorder(byval) # 2,3,1
> > f__ = data.table:::uniqlist(byval, order=o__) # 1,3
> > len__ = data.table:::uniqlengths(f__, nrow(dt)) # 2,1
> > firstofeachgroup = o__[f__] # 2,1
> > origorder = data.table:::iradixorder(firstofeachgroup) # 2,1
> > f__ = f__[origorder] # 3,1
> > len__ = len__[origorder] # 2,1
> > 
> > 
> > Arun
> > 
> > <...snip...> 

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