Meteorological Data Analysis Using MapReduce

Algorithm 5

// Reduce(key, points)

Input: key is the index of the cluster centers, points is the list of the partial sums

from different centers.

Output: key^′,value^′, where key′ is the index of the closet center point,

Value′ is the new center.

(1)  Num = 0;

(2)  While (points.hasNext()){

  currentPoint = points.next();

  Num+ = currentPoint.getnum;

  For (𝑖=0; 𝑖<dimensions; 𝑖++){

   sum[𝑖]+ = currentPoint.point[𝑖];

(3) }

(4) For (𝑖=0; 𝑖<dimentsions; 𝑖++)

 mean[𝑖] = sum[𝑖]/Num;

(5) output key^′,value^′ pair;

(6) End