This should work:
matrix = load 'data1.txt' using PigStorage(',') as (row:chararray,
column:chararray, value:float);
vectors = load 'data2.txt' using PigStorage(',') as (user:chararray,
column:chararray);
joined = join vectors by column, matrix by column;
groups = group joined by (user, row);
result = foreach groups generate group.user, group.row, (float)
SUM(joined.value);
store result into 'result';
Thanks,
Gunther.
On Sun, Oct 21, 2012 at 7:40 PM, jamal sasha <[email protected]> wrote:
> Hi,
> I am trying to do matrix multiplication using pig.
>
> Basically I have data in the form:
> data1.txt
> item1,item2,0.3
> item1, item3, 0.4
> item1, item5, 0.6
>
> And then I another data in the form
> data2.txt
> user1,item1
> user1,item2
> user1,item5
> ...
> user2,item2
> etc
>
> Just to give some context.. I am trying to build a top n recommendation
> system.. which is as follows.
> Matrix formed by data2.txt
> item1 item2 item3 item4 item5
> user1 1 1 0 0 1
>
>
> Matrix formed by data1.txt
>
> item1 item2 item 3 item4 item5
> item1 1 0.3 0.4 0 0.6
> item2 1
> item3 1
> item4 1
> item5 1
>
>
> So recommendations for user1 would be whether user1 is the score
> computation as followed
> Score for user 1 for item 1 = (ignore item1, item1 score) u12* item_12 +
> u13*item_13 + u14*item14 + u15*item15
>
> =
> 1 *0.3 + 0*0.4 + 0*0 + 1 * 0.6 = 0.9
>
> And then i find this score for user1 and item2
>
> And then for user 2 .. item 1 and so on.
>
> I understand this is more of an implementation challenge.. and not sure
> whether this is the right place to ask this.. But any suggestions will be
> greatly appreciated.
> Thanks
> Jamal
>
