A long has 8 bytes :)
On 08.03.2012 14:53, Manuel Blechschmidt wrote:
> Hallo Claudia,
> the reason why longs are use is pure efficiency. When you have a lot of
> things and a lot of users and you are using Strings as identifiers you will
> need a lot of memory just for saving them. Further processes like equals or
> hash codes will take longer.
>
> So a long has 4 bytes (64 bits) a UUID string (e.g.
> 936DA01F-9ABD-4D9D-80C7-02AF85C822A8) encoded as utf-16 has 72 bytes that
> means that UUID would consume more then18x the memory that longs are taking.
>
> /Manuel
>
>
> On 08.03.2012, at 14:27, Claudia Grieco wrote:
>
>> Do you think it's worth the work to change the internal code of Mahout in
>> order to use string identifiers?
>> Thanks
>> Claudia
>>
>> -----Messaggio originale-----
>> Da: Manuel Blechschmidt [mailto:[email protected]]
>> Inviato: lunedì 5 marzo 2012 11.28
>> A: [email protected]
>> Oggetto: Re: Using recommenders with String identifiers
>>
>> Hi Claudia,
>> you have to use an IDMigrator.
>>
>> The following projects shows you an example:
>> https://github.com/ManuelB/facebook-recommender-demo
>>
>> https://github.com/ManuelB/facebook-recommender-demo/blob/master/src/main/ja
>> va/de/apaxo/bedcon/FacebookRecommender.java
>>
>> Good luck
>> Manuel
>>
>> On 05.03.2012, at 09:53, Claudia Grieco wrote:
>>
>>> Hi guys,
>>>
>>> I'd like to use mahout to implement a recommender but I'm encountering a
>>> problem:
>>>
>>> Ids of items and users are represented in Mahout as long integers, while
>> my
>>> data comes from an external database that uses strings to identify items
>> and
>>> users.
>>>
>>> Any suggestion as to how I can fix this problem?
>>>
>>> Thanks a lot
>>>
>>> Claudia
>>>
>>
>> --
>> Manuel Blechschmidt
>> Dortustr. 57
>> 14467 Potsdam
>> Mobil: 0173/6322621
>> Twitter: http://twitter.com/Manuel_B
>>
>>
>
