IS to select slice from 3D DMDA vector : 
IS Object: 1 MPI process
  type: general
Number of indices in set 16
0 0
1 4
2 8
3 12
4 16
5 20
6 24
7 28
8 32
9 36
10 40
11 44
12 48
13 52
14 56
15 60

 Extracted slice vector, in DMDA ordering : 
Vec Object: 1 MPI process
  type: seq
-4.
-6.
-8.
-10.
96.
94.
92.
90.
196.
194.
192.
190.
296.
294.
292.
290.
subset MPI subcomm size is : 1, includes global rank : 0 

 Extracted slice vector, in natural ordering : 
Vec Object: 1 MPI process
  type: mpi
Process [0]
-4.
-6.
-8.
-10.
96.
94.
92.
90.
196.
194.
192.
190.
296.
294.
292.
290.