[R] maximum elements in an ff object?

[Benilton Carvalho]

Oh... I forgot to mention that you can also use the ffdf() approach.
For example, if you're able to load one column at a time, you could do
something like:

res = vector("list", nColumns)
for (i in 1:nColumns)
  res[[i]] = ff(<OneColumnOfData>, ...)
finalFfObj = do.call(ffdf, res)

Of course you can use other aproaches to fill in the ff dataframe....

b

On Fri, Feb 5, 2010 at 11:43 PM, Benilton Carvalho
<beniltoncarvalho at gmail.com> wrote:
> Hi Matt,
>
> you're correct: length(ffObject) must be smaller than 2^31-1... at
> least until R has a 64bit integer type, it seems...
>
> in the meantime, use the bigmemory package. ;-)
>
> b
>
> On Fri, Feb 5, 2010 at 4:18 PM, Matthew Keller <mckellercran at gmail.com> wrote:
>> Hello all,
>>
>> I hate to add to the daily queries regarding R's handling of large
>> datsets ;), but...
>>
>> I read in an online powerpoint about the ff package something about
>> the "length of an ff object" needing to be smaller than
>> .Machine$integer.max. Does anyone know if this means that the # of
>> elements in an ff object must be < .Machine$integer.max [i.e., that ff
>> provides no help with respect to the number of elements in a given
>> object]? I've got a matrix that has 19e9 elements and - even though I
>> can fit it into my ram (using "raw" storage.mode) - R won't let me
>> store it because 19e9 is >> .Machine$integer.max = 2^31.
>>
>> Anyone else have suggestions on how to deal with such massive datasets
>> like the ones I'm using? I'm exploring ncdf as we speak. Best,
>>
>> Matt
>>
>>
>>
>> --
>> Matthew C Keller
>> Asst. Professor of Psychology
>> University of Colorado at Boulder
>> www.matthewckeller.com
>>
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>