[R] storage and single-precision
mbmiller+l at gmail.com
Thu Sep 8 17:14:05 CEST 2011
On Thu, 8 Sep 2011, Duncan Murdoch wrote:
> On 11-09-07 6:25 PM, Mike Miller wrote:
>> I'm getting the impression from on-line docs that R cannot work with
>> single-precision floating-point numbers, but that it has a pseudo-mode
>> for single precision for communication with external programs.
>> I don't mind that R is using doubles internally, but what about
>> storage? If all I need to store is single-precision (32-bit), can I do
>> that? When it is read back into R it can be converted from single to
>> double (back to 64-bit).
>> Furthermore, the data are numbers from 0.000 to 2.000 with no missing
>> values that could be stored just as accurately as unsigned 16-bit
>> integers from 0 to 2000. That would be the best plan for me.
> writeBin is quite flexible in converting between formats if you just
> want to store them on disk. To use nonstandard formats in memory will
> require external support; it's not easy.
Thanks. I can see now that writeBin will store unsigned 16-bit integers,
which is what I want. There is one other issue -- with save() I'm allowed
to use compression (e.g., gzip), but there doesn't seem to be a
compression option in writeBin. Is there a way to get the best of both
worlds? The data are highly nonrandom and at most 11 bits will be used
per integer, so the compression ratio should be pretty good, if I can have
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