the way to compare any two adjacent elements in one rdd

[Zhiliang Zhu]

Hi All,
I would like to compare any two adjacent elements in one given rdd, just as the 
single machine code part:
int a[N] = {...};for (int i=0; i < N - 1; ++i) {   compareFun(a[i], a[i+1]);}...
mapPartitions may work for some situations, however, it could not compare 
elements in different  partitions. foreach also seems not work.
Thanks,Zhiliang