Fix in python API:

[pnorbert]

a. BlocksInfo(name, step)
b. stream.write() sets selection if either 'start' or 'count' is provided (fix for local arrays).

This code below shows the original problem when enumerating the blocks of the v3 variable in the localArray example, where the number of blocks changes across the steps.

#!/usr/bin/env python3
import numpy as np
import adios2

def process_var(varname):
    print("--------------------------")
    print(f"Process variable {varname}")
    v = f.inquire_variable(varname)
    # b = f.all_blocks_info(varname)
    for step in range(v.steps()):
        v.set_step_selection([step, 1])
        bs = f.engine.blocks_info(varname, step)
        for bid in range(len(bs)):   # could use here len(b[step])
            v.set_step_selection([step, 1])
            v.set_block_selection(bid)
            data = f.read(v)
            print(f"step {step} block {bid} len = {len(data)}")


with adios2.FileReader("localArray.bp") as f:
    process_var('v0')
    process_var('v1')
    process_var('v2')
    process_var('v3')

[anagainaru]

I thought start and count need to match in length

[pnorbert]

For local arrays, start is empty, just like shape.