NonlocalBox

A friendly API for simulating nonlocal no-signalling correlations.

Installation

The easiest way to install NonlocalBox is to use the pip command:

python -m pip install nonlocalbox

You may need to replace python with the correct Python interpreter, e.g., python3.

Usage

The following example illustrates a simple game between Alice and Bob. First, we need to create two instances of NonlocalBox, one for Alice and one for Bob:

from os import environ
from nonlocalbox import NonlocalBox

alice_game = NonlocalBox(environ["ALICE_API_KEY"])
bob_game = NonlocalBox(environ["BOB_API_KEY"])

In the current state, neither of them are in any role. Suppose that Alice invites Bob for a simulation, whose username is known by Alice (which is 'bob' in this case). Alice wants to use Popescu-Rohrlich Box of box ID 1 and names it 'hellothere':

alice_game.invite("bob", 1, 'hellothere')
print(alice_game.box_id)  # this is arbitrary
4

In the server side, Bob is automatically added to this box. They both should initialize the newly created box with ID 4. This will set the role 'Alice' to Alice and 'Bob' to Bob (since there won't be any box in Bob's list with ID 4):

alice_game.initialize(4)
bob_game.initialize(4)

They can use the nonlocal boxes to run a simulation.

Suppose Alice sends x = 0 are her input to the box with transaction ID 20220311001 and Bob sends y = 0 with the same transaction ID. Note that for x = y = 0 the results should be correlated:

print(alice_game.use(0, "20220311001"))
0
print(bob_game.use(0, "20220311001"))
0

Now suppose Bob will be the first to send y = 1 with an incremented transaction ID, and Alice also sends x = 1. The results should be anticorrelated:

print(bob_game.use(1, "20220311002"))
1
print(alice_game.use(1, "20220311002"))
0