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From "He Chen" <air...@gmail.com>
Subject How to let key sorted in the final outputfile
Date Tue, 11 Nov 2008 17:05:03 GMT
hi everyone

I use hadoop to do matrix multiplication, I let the key to store the row
information, and let the value be the total row like this:

0 (this is the key)              (0,537040)      (1,217656)  (this string
after the key is value in text)
8                                        (0,641356)      (1,287908)

Now I want to keep the key(LongWritable) in turn from the low to high. I
used the

"config.setOutputKeyComparatorClass(LongWritable.Comparator.class);"

to realize my intent. However, when I multiply two 10x10 matrixes. the key
can not keep in turn. What is the reason?Should I rewrite the comparator?

Chen

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