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From Sean Owen <>
Subject Re: Big Longs in RecommenderJob
Date Mon, 07 Jun 2010 23:46:17 GMT
Really, the mistake here (is mine and) is writing these IDs as signed
values. As used in the recommender bit, the IDs are already
nonnegative longs and so can be written with the current
implementation just fine, if encoded as unsigned.

That is part 2 of what I should change here since it will increase
encoding efficiency a little.

On Tue, Jun 8, 2010 at 12:36 AM, Ted Dunning <> wrote:
> The other solution would be to be satisfied with 62 bits of id space and
> only generate "small" longs.
> On Mon, Jun 7, 2010 at 3:39 PM, Sean Owen <> wrote:
>> Yeah the problem is that signed values are zig-zag encoded into an
>> unsigned value, which loses 1 bit, in addition to losing another bit
>> by mapping to unsigned values.
>> Still there is definitely a way to make it work; the encoding is
>> certainly defined for larger values and there is a need for it. I can
>> work on the right fix.

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