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From Nikolaos Romanos Katsipoulakis <>
Subject Re: Save a UserSimilarity in a File
Date Thu, 17 May 2012 11:57:00 GMT
On 05/17/2012 02:06 PM, Sean Owen wrote:
> I think it will be way too slow to update a file like this, as you must
> seek and rewrite the whole thing. Files aren't for this sort of update. A
> DB might be.
> Even if it were it is probably too slow to read the similarity from backing
> store each time. It needs to be mostly in memory. That's why the caching
> wrapper is probably what you want.
> Sean
> On May 17, 2012 11:25 AM, "Nikolaos Romanos Katsipoulakis"<
>>  wrote:
>> Hey guys,
>> In my recommender i need to save my UserSimilarity (CachingUserSimilarity
>> to be exact) in a file, and whenever I get a request for a recommendation,
>> i need to load it from a file, retrieve the recommendation, and then store
>> it back in a file. Can this be done? I have seen in the mahout
>> documentation a class FileItemSimilarity, which has a constructor that
>> parses the FileItemSimilarity from a file. Is there a similar
>> FileUserSimilarity? How is the FileItemSimilarity represented in the file?
>> Thank you
Thank you for your immediate answer. Hmm, I think you are right. The 
problem is that I want to maintain a static Recommender Object in a web 
service (and use it as a singleton for all invocations of the web 
service), that is updated asynchronously, and is persistent among all 
threads. Do you think that this is a more acceptable design in matter of 

Thank you

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