Am 08.01.2014 09:52, schrieb Riccardo (Jack) Lucchetti:
On Wed, 8 Jan 2014, Sven Schreiber wrote:
> BTW, I have always wondered how gretl actually determines the true/false
> value of something like "indicator == 1" given that the series are
> stored as floating-point values and the corresponding representation
> problems of integers...
Fortunately, dummy variables are not a problem, since both real numbers
0.0 and 1.0 have and exact floating-point representation.
Right, could have thought of that myself. Actually I've just learned
that quite a lot of integers can be represented exactly.
>> 2) Writing binary data
>>
>> Tweaks to our writing of data in text form are be useful, but
>> there's no question that if you want raw speed you're better using
>> C's fwrite and fread to zap big swathes of bytes from RAM to disk or
>> vice versa. I've implemented a --binary option to "store" that
>> causes gretl to write out an XML .gdt file containing the metadata
>> plus a binary .bdt file containing doubles.
>
> Hm, that sounds as if now a .gdt file could indicate either a
> traditional standalone file or a new metadata file, which are quite
> different things, no? A new suffix would seem in order. (.mgdt?)
I wouldn't mind something like that, especially because gdt files have
always been self-contained. With the new "binary" thing, instead, the
dataset is spread between 2 files, with the gdt file containing the
metadata only. The problem is, it would be difficult to tell a
'self-contained' gdt file from a 'metadata-only' gdt file from the
outside, which could be a problem in some cases.
Yep, that's exactly what I meant.
-sven