It may be selected as a test item. Other algorithms can predict the '4'. The test process is random so as to not favor one algorithm. I think you are just arguing that the algorithm you are using isn't good for your data -- so just don't use it. Is that not the answer? I don't know what you mean by the mapping algorithm.
On Wed, May 8, 2013 at 4:17 PM, Zhongduo Lin <zhong...@gmail.com> wrote: > Thank you for your reply. So in the case that item 4 is in the test set, > will Mahout just not take it into consideration or generate any preference > instead? Any is it there any way to evaluate the mapping algorithm in > Mahout? > > Best Regards, > Jimmy >