Thanks, I understand. I am not familiar with the algorithms of non-distributed method.
-----邮件原件----- 发件人: Sean Owen [mailto:[email protected]] 发送时间: 2011年9月20日 18:46 收件人: [email protected] 主题: Re: why use the job 'itemIDIndex' to convert the itemid to index? It is necessary. We want to support input where IDs are possibly 64-bit longs, for consistency with the non-distributed code. But, 64-bit values are too large to be used as indexes into a Vector. So they are hashed and then un-hashed by a dictionary lookup. On Tue, Sep 20, 2011 at 11:44 AM, 张玉东 <[email protected]> wrote: > Yes, the probability of collision is quite small. But I mean it is not > necessary to do this step, I can not find any help of it to the following > computations. >
