Change to multi-buckets using for

using merit to seperate graph, then use multi buckets to execuate
using openmp(low speed up)

maybe du to some problem,low speed up
using openmp(low spped up, has error)

has error when threadnum > 4
Revert "using openmp(low spped up, has error)"

This reverts commit ddd837e50098da4ee63794ba787bee968a98cc70.
Revert "using openmp(low speed up)"

This reverts commit 7e4e45c81bd8cfa5c7bf8e193771950a26b69c7c.