Ray Core Hangs After Seconds of Parallel Execution

[muazhari]

What happened + What you expected to happen

Ray Core hangs after seconds of execution. When using plain Windows, it hangs. When using Windows docker wsl2, it gets an error.

It just does not continue executing and CPU utilization drops.

Expect to not have any errors and is correct.

Versions / Dependencies

ray==2.31.0
pymoo==0.6.1.1

Windows 11
WSL 2.2.4.0
Docker Desktop 4.31.1 (153621)

Reproduction script

The real code is more complex and private. Approximated to:

from pymoo.core.problem import LoopedElementwiseEvaluation, RayParallelization
from pymoo.algorithms.moo.nsga2 import RankAndCrowding
from pymoo.core.mixed import MixedVariableGA
from pymoo.optimize import minimize

from pymoo.core.problem import ElementwiseProblem

import ray

ray.shutdown()
ray.init(dashboard_host="0.0.0.0")
res = ray.available_resources()
print(res)

class MultiObjectiveMixedVariableProblem(ElementwiseProblem):

    def __init__(self, **kwargs):
        vars = {
            "b": Binary(),
            "x": Choice(options=["nothing", "multiply"]),
            "y": Integer(bounds=(-2 * 10 ** 5, 2 * 10 ** 5)),
            "z": Real(bounds=(-5 * 10 ** 3, 5 * 10 ** 3)),
        }
        super().__init__(vars=vars, n_obj=6, n_ieq_constr=0, **kwargs)

    def _evaluate(self, X, out, *args, **kwargs):
        b, x, z, y = X["b"], X["x"], X["z"], X["y"]
        f1 = z ** 2 + y ** 2
        f2 = (z + 2) ** 2 + (y - 1) ** 2
        f3 = (z ** 2) / 2 + (y + 1)
        f4 = -z ** 2
        f5 = z ** 2
        f6 = z / 2 - y - y / z
        
        if b:
            f2 = 100 * f2
         
        if x == "multiply":
            f2 = 10 * f2

        out["F"] = [f1, f2, f3, f4, f5, f6]


runner = RayParallelization(
    job_resources={
        "num_gpus": int(res["GPU"]),
        "num_cpus": int(res["CPU"]),
    }
)


problem = MultiObjectiveMixedVariableProblem(elementwise_runner=runner)

algorithm = MixedVariableGA(
    survival=RankAndCrowding()
)

res = minimize(
    problem,
    algorithm,
    verbose=True,
    seed=1
)

Issue Severity

High: It blocks me from completing my task.