# Owner(s): ["module: optimizer"]

import torch
from torch.optim import (
    Adadelta, Adagrad, Adam, Adamax, AdamW, ASGD, NAdam, RAdam, RMSprop, Rprop, SGD
)
from torch.testing._internal.common_utils import (
    TestCase,
    load_tests,
    gradcheck,
    skipIfTorchDynamo
)


# load_tests from common_utils is used to automatically filter tests for
# sharding on sandcastle. This line silences flake warnings
load_tests = load_tests


def _diff_fn(p, grad, opt_differentiable_state, opt_class, kwargs, *ignored):
    # Ignored is the list of values in `opt_differentiable_state`, we do this
    # for `gradcheck` to correctly track the state tensors as function inputs
    # because otherwise it can't unpack the values in the `opt_differentiable_state`
    # dict
    p = p.clone()
    p.grad = grad
    opt_differentiable_state = {
        k: v.clone() if isinstance(v, torch.Tensor) else v
        for k, v in opt_differentiable_state.items()
    }
    opt = opt_class([p], **kwargs)
    opt.state[p].update(opt_differentiable_state)
    opt.step()
    return (p,) + tuple(
        v
        for v in opt.state[p].values()
        if isinstance(v, torch.Tensor) and v.requires_grad
    )


@skipIfTorchDynamo("Differentiable optimizers not supported")
class TestDifferentiableOptimizer(TestCase):

    def test_sgd(self):
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        mbuff = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state = {"momentum_buffer": mbuff}
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                SGD,
                {"lr": 0.9, "differentiable": True},
                *state.values(),
            ),
        )


    def test_adam(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["exp_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["exp_avg_sq"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["max_exp_avg_sq"] = torch.rand(
            10, requires_grad=True, dtype=torch.float64
        )

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                Adam,
                {"lr": 0.9, "differentiable": True, "amsgrad": True},
                *state.values(),
            ),
        )


    def test_rmsprop(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["step"] = torch.zeros((), dtype=torch.float64)
        state["square_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["momentum_buffer"] = torch.rand(
            10, requires_grad=True, dtype=torch.float64
        )
        # This can cause issues with large values and nan due to sqrt ops
        state["grad_avg"] = 1e-2 * torch.rand(
            10, requires_grad=True, dtype=torch.float64
        )
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                RMSprop,
                {
                    "lr": 0.9,
                    "maximize": True,
                    "momentum": 0.9,
                    "differentiable": True,
                    "centered": True,
                    "weight_decay": 0.1,
                },
                *state.values(),
            ),
        )


    def test_adadelta(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["square_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["acc_delta"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                Adadelta,
                {"lr": 0.9, "weight_decay": 0.1, "differentiable": True},
                *state.values(),
            ),
        )


    def test_adagrad(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["sum"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                Adagrad,
                {"lr": 0.9, "weight_decay": 0.1, "differentiable": True},
                *state.values(),
            ),
        )


    def test_adamax(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["exp_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["exp_inf"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                Adamax,
                {"lr": 0.9, "weight_decay": 0.1, "differentiable": True},
                *state.values(),
            ),
        )


    @skipIfTorchDynamo("The inplace mu update fails with dynamo, "
                       "since this is only happening when differentiable is enabled, skipping for now")
    def test_asgd(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` `eta` & `mu` are not continuous variables (even though we define them as floats)
        # and so they shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["eta"] = torch.tensor(0.9, requires_grad=False, dtype=torch.float64)
        state["mu"] = torch.tensor(1.0, requires_grad=False, dtype=torch.float64)
        state["ax"] = torch.rand(10, requires_grad=True, dtype=torch.float64)

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                ASGD,
                {"lr": 0.9, "differentiable": True},
                *state.values(),
            ),
        )

    def test_rprop(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["prev"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["step_size"] = torch.rand(10, requires_grad=True, dtype=torch.float64)

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                Rprop,
                {"lr": 0.9, "differentiable": True},
                *state.values(),
            ),
        )

    def test_adamw(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["exp_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["exp_avg_sq"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["max_exp_avg_sq"] = torch.rand(
            10, requires_grad=True, dtype=torch.float64
        )

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                AdamW,
                {"lr": 0.9, "differentiable": True, "amsgrad": True},
                *state.values(),
            ),
        )

    def test_nadam(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["exp_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["exp_avg_sq"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["mu_product"] = torch.tensor(1.0, requires_grad=True, dtype=torch.float64)

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                NAdam,
                {"lr": 0.9, "differentiable": True},
                *state.values(),
            ),
        )

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                NAdam,
                {"lr": 0.9, "decoupled_weight_decay": True, "differentiable": True},
                *state.values(),
            ),
        )

    def test_radam(self):
        state = {}
        p = torch.rand(10, requires_grad=True, dtype=torch.float64)
        grad = torch.rand(10, requires_grad=True, dtype=torch.float64)
        # `step` is not a continuous variable (even though we define it as a float)
        # and so it shouldn't require gradients.
        state["step"] = torch.tensor(10.0, requires_grad=False, dtype=torch.float64)
        state["exp_avg"] = torch.rand(10, requires_grad=True, dtype=torch.float64)
        state["exp_avg_sq"] = torch.rand(10, requires_grad=True, dtype=torch.float64)

        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                RAdam,
                {"lr": 0.9, "differentiable": True},
                *state.values(),
            ),
        )
        gradcheck(
            _diff_fn,
            (
                p,
                grad,
                state,
                RAdam,
                {"lr": 0.9, "weight_decay": 0.1, "decoupled_weight_decay": True, "differentiable": True},
                *state.values(),
            ),
        )


if __name__ == "__main__":
    print("These tests should be run through test/test_optim.py instead")