//  [python]
def forward(self, training_window_size):
        if training_window_size == self.window_size:
            relative_position_bias = \
                self.relative_position_bias_table[self.relative_position_index.view(-1)].view(
                    self.window_size[0] * self.window_size[1] + 1,
                    self.window_size[0] * self.window_size[1] + 1, -1)  # Wh*Ww,Wh*Ww,nH
            relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous()  # nH, Wh*Ww, Wh*Ww
        else:
            training_window_size = tuple(training_window_size.tolist())
            new_num_relative_distance = (2 * training_window_size[0] - 1) * (2 * training_window_size[1] - 1) + 3
            # new_num_relative_dis 为 所有可能的相对位置选项，包含cls-cls，tok-cls，与cls-tok
            new_relative_position_bias_table = t.upsample_bicubic(
                self.relative_position_bias_table[:-3, :].permute(1, 0).view(1, self.num_heads,
                                                                             2 * self.window_size[0] - 1,
                                                                             2 * self.window_size[1] - 1),
                size=(2 * training_window_size[0] - 1, 2 * training_window_size[1] - 1))
            new_relative_position_bias_table = new_relative_position_bias_table.view(self.num_heads,
                                                                                     new_num_relative_distance - 3).permute(
                1, 0)
            new_relative_position_bias_table = torch.cat(
                [new_relative_position_bias_table, self.relative_position_bias_table[-3::]], dim=0)

            # get pair-wise relative position index for each token inside the window
            coords_h = torch.arange(training_window_size[0])
            coords_w = torch.arange(training_window_size[1])
            coords = torch.stack(torch.meshgrid([coords_h, coords_w]))  # 2, Wh, Ww
            coords_flatten = torch.flatten(coords, 1)  # 2, Wh*Ww
            relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :]  # 2, Wh*Ww, Wh*Ww
            relative_coords = relative_coords.permute(1, 2, 0).contiguous()  # Wh*Ww, Wh*Ww, 2
            relative_coords[:, :, 0] += training_window_size[0] - 1  # shift to start from 0
            relative_coords[:, :, 1] += training_window_size[1] - 1
            relative_coords[:, :, 0] *= 2 * training_window_size[1] - 1
            relative_position_index = \
                torch.zeros(size=(training_window_size[0] * training_window_size[1] + 1,) * 2,
                            dtype=relative_coords.dtype)
            relative_position_index[1:, 1:] = relative_coords.sum(-1)  # Wh*Ww, Wh*Ww
            relative_position_index[0, 0:] = new_num_relative_distance - 3
            relative_position_index[0:, 0] = new_num_relative_distance - 2
            relative_position_index[0, 0] = new_num_relative_distance - 1

            relative_position_bias = \
                new_relative_position_bias_table[relative_position_index.view(-1)].view(
                    training_window_size[0] * training_window_size[1] + 1,
                    training_window_size[0] * training_window_size[1] + 1, -1)  # Wh*Ww,Wh*Ww,nH
            relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous()  # nH, Wh*Ww, Wh*Ww

        return relative_position_bias