bpls2 + Global Value over many steps: min/max incorrect

Created by: pnorbert

Global (one per application) value written every step: the min and max is undetermined, or equals to the value in the first step. It should be calculated from the values across the steps when reading from a file. See variable Step from example values_write:

ADIOS2/build$ mpirun -n 4 ./bin/values_write 

ADIOS2/build$ ./bin/bpls2 values.bp -l
  unsigned int  Nparts     5*scalar = 0 / 6
  int           Nproc      scalar = 4
  int           ProcessID  scalar = 0
  int           Step       5*scalar = 0 / 0

ADIOS2/build$ ./bin/bpls2 values.bp -lDd Step
  int           Step       5*scalar = 0 / 0
        step 0: 1 instances available
               0
        step 1: 1 instances available
               1
        step 2: 1 instances available
               2
        step 3: 1 instances available
               3
        step 4: 1 instances available
               4

The min/max should be 0/5 in this example.