CUDT: A CUDA Based Decision Tree Algorithm

Algorithm 4

Algorithm of finding split point function.

Algorithm  Finding Split Points

Input:   A Set of attribute lists 𝐴 which comprised by rid, value, label

Output:  A winning attribute 𝑊

     Index of split point 𝑋

(1) For each attribute list 𝐴_𝑖  do in parallel

(2)   𝐶_𝑖← Scan(𝐴_𝑖.𝑙𝑎𝑏𝑒𝑙)

(3)   For each data of 𝐴_𝑖  do in parallel

(4)     IsSplitPointFlag_𝑖[𝑗] = (𝐴_𝑖.𝑣𝑎𝑙𝑢𝑒_𝑗 != 𝐴_𝑖.𝑣𝑎𝑙𝑢𝑒_𝑗+1) ? 1 : 0

(5)   Addr_𝑖← Scan(IsSplitPointFlag_𝑖)

(6)   Compact(𝐶_𝑖, IsSplitPointFlag_𝑖, Addr_𝑖)

(7)   value_𝑖← SplitCriteria(𝐶_𝑖)

(8) Reduce(value)

(9) Return  𝑊,𝑋