charm4py.readonlies is an object that serves as a container for data that the application wants to broadcast to every process after the “entry point” has executed. Attributes added to readonlies during execution of the entry point will become available in the readonlies instance of every process.

For example:

from charm4py import charm, Chare, Group
from charm4py import readonlies as ro

class Test(Chare):
    def __init__(self):
        # this will print 3 and 5 on every PE
        print(ro.x, ro.y)

def main(args):
    ro.x = 3
    ro.y = 5



Names of attributes added to readonlies must not start or end with ‘_’.

As the name implies, data in readonlies is intended to be read-only. This is because the broadcast is done only once, and after this there is no synchronization of the data.