## March 12, 2009

### Find the maximum absolute row sum of matrix using MapReduce

The find the maximum absolute row sum of matrix is a good fit with MapReduce model as below.
                                         j=nThe maximum absolute row sum =   max   ( sum | a_{i,j} | )                                1<=i<=n   j=1- A map task receives a row n as a key, and vector of each row as its value - emit (row, the sum of the absolute value of each entries)- Reduce task select the maximum one

Maybe it can be written in java as below.
  Vector v = givenValue;  double rowSum;  for(VectorEntry e : v) {    rowSum += Math.abs(e.get(i));  }

See more of the Hama - Algorithms