def run()

in classy_vision/distributed/launch_ray.py [0:0]
51 lines of code
13 McCabe index (conditional complexity)

    def run(self, master_addr, master_port, node_rank, dist_world_size, args):
        processes = []

        # set PyTorch distributed related environmental variables
        current_env = os.environ.copy()
        current_env["MASTER_ADDR"] = master_addr
        current_env["MASTER_PORT"] = str(master_port)
        current_env["WORLD_SIZE"] = str(dist_world_size)

        if "OMP_NUM_THREADS" not in os.environ and args.nproc_per_node > 1:
            current_env["OMP_NUM_THREADS"] = str(1)
            print(
                "*****************************************\n"
                "Setting OMP_NUM_THREADS environment variable for each process "
                "to be {} in default, to avoid your system being overloaded, "
                "please further tune the variable for optimal performance in "
                "your application as needed. \n"
                "*****************************************".format(
                    current_env["OMP_NUM_THREADS"]
                )
            )

        # Set the init_method and rank of the process for distributed training.
        for local_rank in range(0, args.nproc_per_node):
            # each process's rank
            dist_rank = args.nproc_per_node * node_rank + local_rank
            current_env["RANK"] = str(dist_rank)
            current_env["LOCAL_RANK"] = str(local_rank)

            # spawn the processes
            with_python = not args.no_python
            cmd = []
            if with_python:
                cmd = [sys.executable, "-u"]
                if args.module:
                    cmd.append("-m")
            else:
                if not args.use_env:
                    raise ValueError(
                        "When using the '--no_python' flag, "
                        "you must also set the '--use_env' flag."
                    )
                if args.module:
                    raise ValueError(
                        "Don't use both the '--no_python' flag"
                        "and the '--module' flag at the same time."
                    )

            cmd.append(args.training_script)

            if not args.use_env:
                cmd.append("--local_rank={}".format(local_rank))

            cmd.extend(args.training_script_args)
            process = subprocess.Popen(cmd, env=current_env)
            processes.append(process)

        for process in processes:
            process.wait()
            if process.returncode != 0:
                raise subprocess.CalledProcessError(
                    returncode=process.returncode, cmd=cmd
                )