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# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2021.03 #
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import torch
import torch.nn as nn

import math
from typing import Optional, Union

import spaces
from .super_module import SuperModule
from .super_module import SuperRunMode

IntSpaceType = Union[int, spaces.Integer, spaces.Categorical]
BoolSpaceType = Union[bool, spaces.Categorical]


class SuperLinear(SuperModule):
    """Applies a linear transformation to the incoming data: :math:`y = xA^T + b`"""

    def __init__(
        self,
        in_features: IntSpaceType,
        out_features: IntSpaceType,
        bias: BoolSpaceType = True,
    ) -> None:
        super(SuperLinear, self).__init__()

        # the raw input args
        self._in_features = in_features
        self._out_features = out_features
        self._bias = bias

        self._super_weight = torch.nn.Parameter(
            torch.Tensor(self.out_features, self.in_features)
        )
        if self.bias:
            self._super_bias = torch.nn.Parameter(torch.Tensor(self.out_features))
        else:
            self.register_parameter("_super_bias", None)
        self.reset_parameters()

    @property
    def in_features(self):
        return spaces.get_max(self._in_features)

    @property
    def out_features(self):
        return spaces.get_max(self._out_features)

    @property
    def bias(self):
        return spaces.has_categorical(self._bias, True)

    def abstract_search_space(self):
        print('-')

    def reset_parameters(self) -> None:
        nn.init.kaiming_uniform_(self._super_weight, a=math.sqrt(5))
        if self.bias:
            fan_in, _ = nn.init._calculate_fan_in_and_fan_out(self._super_weight)
            bound = 1 / math.sqrt(fan_in)
            nn.init.uniform_(self._super_bias, -bound, bound)

    def forward_raw(self, input: torch.Tensor) -> torch.Tensor:
        return F.linear(input, self._super_weight, self._super_bias)

    def extra_repr(self) -> str:
        return "in_features={:}, out_features={:}, bias={:}".format(
            self.in_features, self.out_features, self.bias
        )


class SuperMLP(nn.Module):
    # MLP: FC -> Activation -> Drop -> FC -> Drop
    def __init__(
        self,
        in_features,
        hidden_features: Optional[int] = None,
        out_features: Optional[int] = None,
        act_layer=nn.GELU,
        drop: Optional[float] = None,
    ):
        super(MLP, self).__init__()
        out_features = out_features or in_features
        hidden_features = hidden_features or in_features
        self.fc1 = nn.Linear(in_features, hidden_features)
        self.act = act_layer()
        self.fc2 = nn.Linear(hidden_features, out_features)
        self.drop = nn.Dropout(drop or 0)

    def forward(self, x):
        x = self.fc1(x)
        x = self.act(x)
        x = self.drop(x)
        x = self.fc2(x)
        x = self.drop(x)
        return x