def get_optimizer()

in src/optim.py [0:0]

• 61 lines of code
• 15 McCabe index (conditional complexity)

def get_optimizer(parameters, s):
    """
    Parse optimizer parameters.
    Input should be of the form:
        - "sgd,lr=0.01"
        - "adagrad,lr=0.1,lr_decay=0.05"
    """
    if "," in s:
        method = s[: s.find(",")]
        optim_params = {}
        for x in s[s.find(",") + 1 :].split(","):
            split = x.split("=")
            assert len(split) == 2
            assert re.match(r"^[+-]?(\d+(\.\d*)?|\.\d+)$", split[1]) is not None
            optim_params[split[0]] = float(split[1])
    else:
        method = s
        optim_params = {}

    if method == "adadelta":
        optim_fn = optim.Adadelta
    elif method == "adagrad":
        optim_fn = optim.Adagrad
    elif method == "adam":
        optim_fn = Adam
        optim_params["betas"] = (
            optim_params.get("beta1", 0.9),
            optim_params.get("beta2", 0.999),
        )
        optim_params.pop("beta1", None)
        optim_params.pop("beta2", None)
    elif method == "adam_inverse_sqrt":
        optim_fn = AdamInverseSqrtWithWarmup
        optim_params["betas"] = (
            optim_params.get("beta1", 0.9),
            optim_params.get("beta2", 0.999),
        )
        optim_params.pop("beta1", None)
        optim_params.pop("beta2", None)
    elif method == "adam_cosine":
        optim_fn = AdamCosineWithWarmup
        optim_params["betas"] = (
            optim_params.get("beta1", 0.9),
            optim_params.get("beta2", 0.999),
        )
        optim_params.pop("beta1", None)
        optim_params.pop("beta2", None)
    elif method == "adamax":
        optim_fn = optim.Adamax
    elif method == "asgd":
        optim_fn = optim.ASGD
    elif method == "rmsprop":
        optim_fn = optim.RMSprop
    elif method == "rprop":
        optim_fn = optim.Rprop
    elif method == "sgd":
        optim_fn = optim.SGD
        assert "lr" in optim_params
    else:
        raise Exception('Unknown optimization method: "%s"' % method)

    # check that we give good parameters to the optimizer
    expected_args = inspect.getargspec(optim_fn.__init__)[0]
    assert expected_args[:2] == ["self", "params"]
    if not all(k in expected_args[2:] for k in optim_params.keys()):
        raise Exception(
            'Unexpected parameters: expected "%s", got "%s"'
            % (str(expected_args[2:]), str(optim_params.keys()))
        )

    return optim_fn(parameters, **optim_params)