# Re: [Rd] Use logical expresion on ff object

Date: Fri, 19 Aug 2011 02:03:03 -0700 (PDT)

It's not corect. Vector with length 15*10^6 you could store in memory without ff packages.
For vector 15*10^7

k=bit(15*10^7)
a=ff(2,15*10^7)
system.time(k<-a[,chunk(1,length.ff(a),1e4)]<1)

Error: cannot allocate vector of size 572.2 Mb In addition: Warning messages:
1: In system.time(k <- a[, chunk(1, length.ff(a), 10000)] < 1) :   Reached total allocation of 1535Mb: see help(memory.size) 2: In system.time(k <- a[, chunk(1, length.ff(a), 10000)] < 1) :   Reached total allocation of 1535Mb: see help(memory.size) 3: In system.time(k <- a[, chunk(1, length.ff(a), 10000)] < 1) :   Reached total allocation of 1535Mb: see help(memory.size) 4: In system.time(k <- a[, chunk(1, length.ff(a), 10000)] < 1) :   Reached total allocation of 1535Mb: see help(memory.size) Timing stopped at: 2.13 0.84 10.45

And you don't understand my question. In simple operation in R I could do: a=c(1,4,5,6)
b=a[a>1]
b
[1] 4 5 6

If a is ff object (for example length=15*10^7) this operation doesn't work. Mayby I don't understand something or this operation is not definied currently in this package.
In summarizing:
I have very long vector stored in ff object and I want to chse elements from this vector which fulfil logical expresion (for example a>1).

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Received on Fri 19 Aug 2011 - 09:05:23 GMT

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