Usage

The following is simple example HELICS federation implemented in Python. The example files containing this code can be found here. The federation can be run from the command line with

$ helics run --path=runner.json

Many more Python-based HELICS examples can be found in the HELICS Examples repository with many of them having corresponding documentation in the HELICS User Guide

Broker

import helics as h
import time

broker = h.helicsCreateBroker("zmq", "", "-f 2 --loglevel=trace")

while h.helicsBrokerIsConnected(broker):
    time.sleep(1)

Federate 1

import time
import helics as h
from math import pi

fedinfo = h.helicsCreateFederateInfo()

h.helicsFederateInfoSetCoreName(fedinfo, "Federate1")
h.helicsFederateInfoSetCoreTypeFromString(fedinfo, "zmq")
h.helicsFederateInfoSetCoreInitString(fedinfo, "--federates=1")
h.helicsFederateInfoSetTimeProperty(fedinfo, h.HELICS_PROPERTY_TIME_DELTA, 0.01)

vfed = h.helicsCreateValueFederate("Federate1", fedinfo)

pub = h.helicsFederateRegisterGlobalTypePublication(vfed, "topic_name", "double", "")

h.helicsFederateEnterExecutingMode(vfed)

this_time = 0.0

for t in range(5, 10):

    currenttime = h.helicsFederateRequestTime(vfed, t)

    h.helicsPublicationPublishDouble(pub, pi)
    print("SENDER: Sending value pi = {} at time {} to RECEIVER".format(pi, currenttime))

    time.sleep(1)

h.helicsFederateDisconnect(vfed)
h.helicsFederateDestroy(vfed)

Federate 2

import helics as h

fedinfo = h.helicsCreateFederateInfo()
h.helicsFederateInfoSetCoreName(fedinfo, "Federate2")
h.helicsFederateInfoSetCoreTypeFromString(fedinfo, "zmq")
h.helicsFederateInfoSetCoreInitString(fedinfo, "--federates=1")
h.helicsFederateInfoSetTimeProperty(fedinfo, h.HELICS_PROPERTY_TIME_DELTA, 0.01)

vfed = h.helicsCreateValueFederate("Federate2", fedinfo)

sub = h.helicsFederateRegisterSubscription(vfed, "topic_name", "")

h.helicsFederateEnterExecutingMode(vfed)

value = 0.0
currenttime = -1

while currenttime <= 100:

    currenttime = h.helicsFederateRequestTime(vfed, 100)

    value = h.helicsInputGetString(sub)
    print("RECEIVER: Received value = {} at time {} from SENDER".format(value, currenttime))

h.helicsFederateDisconnect(vfed)
h.helicsFederateDestroy(vfed)