FEDformer

FEDformer模型旨在解决在长时间预测中寻找可靠依赖关系的挑战,特别是在复杂的时间模式上。

该架构具有以下独特特征: - 基于移动平均滤波器的趋势和季节性分量的内置渐进分解。 - 频率增强块和频率增强注意力,以便在稀疏表示上执行注意力,例如傅里叶变换。 - Vaswani等人(2017)提出的经典编码器-解码器,结合多头注意力机制。

FEDformer模型利用三组分的方法来定义其嵌入: - 它采用从卷积网络获得的编码自回归特征。 - 利用从日历特征获得的绝对位置嵌入。

参考文献
- Zhou, Tian, Ziqing Ma, Qingsong Wen, Xue Wang, Liang Sun, 和 Rong Jin.. “FEDformer: 频率增强分解变压器用于长期序列预测”

图 1. FEDformer 架构。
import numpy as np
from typing import Optional

import torch
import torch.nn as nn
import torch.nn.functional as F

from neuralforecast.common._modules import DataEmbedding
from neuralforecast.common._modules import SeriesDecomp
from neuralforecast.common._base_windows import BaseWindows

from neuralforecast.losses.pytorch import MAE

1. 辅助函数

    
class LayerNorm(nn.Module):
    """
    专门为季节性部分设计的层归一化
    """
    def __init__(self, channels):
        super(LayerNorm, self).__init__()
        self.layernorm = nn.LayerNorm(channels)

    def forward(self, x):
        x_hat = self.layernorm(x)
        bias = torch.mean(x_hat, dim=1).unsqueeze(1).repeat(1, x.shape[1], 1)
        return x_hat - bias


class AutoCorrelationLayer(nn.Module):
    """
    自相关层
    """
    def __init__(self, correlation, hidden_size, n_head, d_keys=None,
                 d_values=None):
        super(AutoCorrelationLayer, self).__init__()

        d_keys = d_keys or (hidden_size // n_head)
        d_values = d_values or (hidden_size // n_head)

        self.inner_correlation = correlation
        self.query_projection = nn.Linear(hidden_size, d_keys * n_head)
        self.key_projection = nn.Linear(hidden_size, d_keys * n_head)
        self.value_projection = nn.Linear(hidden_size, d_values * n_head)
        self.out_projection = nn.Linear(d_values * n_head, hidden_size)
        self.n_head = n_head

    def forward(self, queries, keys, values, attn_mask):
        B, L, _ = queries.shape
        _, S, _ = keys.shape
        H = self.n_head

        queries = self.query_projection(queries).view(B, L, H, -1)
        keys = self.key_projection(keys).view(B, S, H, -1)
        values = self.value_projection(values).view(B, S, H, -1)

        out, attn = self.inner_correlation(
            queries,
            keys,
            values,
            attn_mask
        )
        out = out.view(B, L, -1)

        return self.out_projection(out), attn
class EncoderLayer(nn.Module):
    """
    具有渐进分解架构的FEDformer编码器层
    """
    def __init__(self, attention, hidden_size, conv_hidden_size=None, MovingAvg=25, dropout=0.1, activation="relu"):
        super(EncoderLayer, self).__init__()
        conv_hidden_size = conv_hidden_size or 4 * hidden_size
        self.attention = attention
        self.conv1 = nn.Conv1d(in_channels=hidden_size, out_channels=conv_hidden_size, kernel_size=1, bias=False)
        self.conv2 = nn.Conv1d(in_channels=conv_hidden_size, out_channels=hidden_size, kernel_size=1, bias=False)
        self.decomp1 = SeriesDecomp(MovingAvg)
        self.decomp2 = SeriesDecomp(MovingAvg)
        self.dropout = nn.Dropout(dropout)
        self.activation = F.relu if activation == "relu" else F.gelu

    def forward(self, x, attn_mask=None):
        new_x, attn = self.attention(
            x, x, x,
            attn_mask=attn_mask
        )
        x = x + self.dropout(new_x)
        x, _ = self.decomp1(x)
        y = x
        y = self.dropout(self.activation(self.conv1(y.transpose(-1, 1))))
        y = self.dropout(self.conv2(y).transpose(-1, 1))
        res, _ = self.decomp2(x + y)
        return res, attn


class Encoder(nn.Module):
    """
    FEDformer编码器
    """
    def __init__(self, attn_layers, conv_layers=None, norm_layer=None):
        super(Encoder, self).__init__()
        self.attn_layers = nn.ModuleList(attn_layers)
        self.conv_layers = nn.ModuleList(conv_layers) if conv_layers is not None else None
        self.norm = norm_layer

    def forward(self, x, attn_mask=None):
        attns = []
        if self.conv_layers is not None:
            for attn_layer, conv_layer in zip(self.attn_layers, self.conv_layers):
                x, attn = attn_layer(x, attn_mask=attn_mask)
                x = conv_layer(x)
                attns.append(attn)
            x, attn = self.attn_layers[-1](x)
            attns.append(attn)
        else:
            for attn_layer in self.attn_layers:
                x, attn = attn_layer(x, attn_mask=attn_mask)
                attns.append(attn)

        if self.norm is not None:
            x = self.norm(x)

        return x, attns


class DecoderLayer(nn.Module):
    """
    具有渐进分解架构的FEDformer解码器层
    """
    def __init__(self, self_attention, cross_attention, hidden_size, c_out, conv_hidden_size=None,
                 MovingAvg=25, dropout=0.1, activation="relu"):
        super(DecoderLayer, self).__init__()
        conv_hidden_size = conv_hidden_size or 4 * hidden_size
        self.self_attention = self_attention
        self.cross_attention = cross_attention
        self.conv1 = nn.Conv1d(in_channels=hidden_size, out_channels=conv_hidden_size, kernel_size=1, bias=False)
        self.conv2 = nn.Conv1d(in_channels=conv_hidden_size, out_channels=hidden_size, kernel_size=1, bias=False)
        self.decomp1 = SeriesDecomp(MovingAvg)
        self.decomp2 = SeriesDecomp(MovingAvg)
        self.decomp3 = SeriesDecomp(MovingAvg)
        self.dropout = nn.Dropout(dropout)
        self.projection = nn.Conv1d(in_channels=hidden_size, out_channels=c_out, kernel_size=3, stride=1, padding=1,
                                    padding_mode='circular', bias=False)
        self.activation = F.relu if activation == "relu" else F.gelu

    def forward(self, x, cross, x_mask=None, cross_mask=None):
        x = x + self.dropout(self.self_attention(
            x, x, x,
            attn_mask=x_mask
        )[0])
        x, trend1 = self.decomp1(x)
        x = x + self.dropout(self.cross_attention(
            x, cross, cross,
            attn_mask=cross_mask
        )[0])
        x, trend2 = self.decomp2(x)
        y = x
        y = self.dropout(self.activation(self.conv1(y.transpose(-1, 1))))
        y = self.dropout(self.conv2(y).transpose(-1, 1))
        x, trend3 = self.decomp3(x + y)

        residual_trend = trend1 + trend2 + trend3
        residual_trend = self.projection(residual_trend.permute(0, 2, 1)).transpose(1, 2)
        return x, residual_trend


class Decoder(nn.Module):
    """
    FEDformer解码器
    """
    def __init__(self, layers, norm_layer=None, projection=None):
        super(Decoder, self).__init__()
        self.layers = nn.ModuleList(layers)
        self.norm = norm_layer
        self.projection = projection

    def forward(self, x, cross, x_mask=None, cross_mask=None, trend=None):
        for layer in self.layers:
            x, residual_trend = layer(x, cross, x_mask=x_mask, cross_mask=cross_mask)
            trend = trend + residual_trend

        if self.norm is not None:
            x = self.norm(x)

        if self.projection is not None:
            x = self.projection(x)
        return x, trend
def get_frequency_modes(seq_len, modes=64, mode_select_method='random'):
    """
    获取频域模式:
        'random' 用于随机采样
        'else' 用于采样最低模式;
    """
    modes = min(modes, seq_len//2)
    if mode_select_method == 'random':
        index = list(range(0, seq_len // 2))
        np.random.shuffle(index)
        index = index[:modes]
    else:
        index = list(range(0, modes))
    index.sort()
    return index


class FourierBlock(nn.Module):
    """
    傅里叶块
    """
    def __init__(self, in_channels, out_channels, seq_len, modes=0, mode_select_method='random'):
        super(FourierBlock, self).__init__()
        # 获取频域模式
        self.index = get_frequency_modes(seq_len, modes=modes, mode_select_method=mode_select_method)

        self.scale = (1 / (in_channels * out_channels))
        self.weights1 = nn.Parameter(
            self.scale * torch.rand(8, in_channels // 8, out_channels // 8, len(self.index), dtype=torch.cfloat))

    # 复乘法
    def compl_mul1d(self, input, weights):
        # (批次, 输入通道, x), (输入通道, 输出通道, x) -> (批次, 输出通道, x)
        return torch.einsum("bhi,hio->bho", input, weights)

    def forward(self, q, k, v, mask):
        # 尺寸 = [批次大小, 长度, 隐藏层大小, 嵌入维度]
        B, L, H, E = q.shape
        
        x = q.permute(0, 2, 3, 1)
        # 计算傅里叶系数
        x_ft = torch.fft.rfft(x, dim=-1)
        # 执行傅里叶神经操作
        out_ft = torch.zeros(B, H, E, L // 2 + 1, device=x.device, dtype=torch.cfloat)
        for wi, i in enumerate(self.index):
            out_ft[:, :, :, wi] = self.compl_mul1d(x_ft[:, :, :, i], self.weights1[:, :, :, wi])
        # 返回时域
        x = torch.fft.irfft(out_ft, n=x.size(-1))
        return (x, None)

class FourierCrossAttention(nn.Module):
    """
    傅里叶交叉注意力层
    """    
    def __init__(self, in_channels, out_channels, seq_len_q, seq_len_kv, modes=64, mode_select_method='random',
                 activation='tanh', policy=0):
        super(FourierCrossAttention, self).__init__()
        self.activation = activation
        self.in_channels = in_channels
        self.out_channels = out_channels
        # 在频域中获取查询和键(及值)的模式
        self.index_q = get_frequency_modes(seq_len_q, modes=modes, mode_select_method=mode_select_method)
        self.index_kv = get_frequency_modes(seq_len_kv, modes=modes, mode_select_method=mode_select_method)

        self.scale = (1 / (in_channels * out_channels))
        self.weights1 = nn.Parameter(
            self.scale * torch.rand(8, in_channels // 8, out_channels // 8, len(self.index_q), dtype=torch.cfloat))

    # 复乘法
    def compl_mul1d(self, input, weights):
        # (批次, 输入通道, x), (输入通道, 输出通道, x) -> (批次, 输出通道, x)
        return torch.einsum("bhi,hio->bho", input, weights)

    def forward(self, q, k, v, mask):
        # 尺寸 = [批次大小, 长度, 隐藏层大小, 嵌入维度]
        B, L, H, E = q.shape
        xq = q.permute(0, 2, 3, 1)  # 尺寸 = [批次大小, 头数, 嵌入维度, 层数]
        xk = k.permute(0, 2, 3, 1)
        #xv = v.permute(0, 2, 3, 1)

        # 计算傅里叶系数
        xq_ft_ = torch.zeros(B, H, E, len(self.index_q), device=xq.device, dtype=torch.cfloat)
        xq_ft = torch.fft.rfft(xq, dim=-1)
        for i, j in enumerate(self.index_q):
            xq_ft_[:, :, :, i] = xq_ft[:, :, :, j]
        xk_ft_ = torch.zeros(B, H, E, len(self.index_kv), device=xq.device, dtype=torch.cfloat)
        xk_ft = torch.fft.rfft(xk, dim=-1)
        for i, j in enumerate(self.index_kv):
            xk_ft_[:, :, :, i] = xk_ft[:, :, :, j]

        # 频域注意力机制
        xqk_ft = (torch.einsum("bhex,bhey->bhxy", xq_ft_, xk_ft_))
        if self.activation == 'tanh':
            xqk_ft = xqk_ft.tanh()
        elif self.activation == 'softmax':
            xqk_ft = torch.softmax(abs(xqk_ft), dim=-1)
            xqk_ft = torch.complex(xqk_ft, torch.zeros_like(xqk_ft))
        else:
            raise Exception('{} actiation function is not implemented'.format(self.activation))
        xqkv_ft = torch.einsum("bhxy,bhey->bhex", xqk_ft, xk_ft_)
        xqkvw = torch.einsum("bhex,heox->bhox", xqkv_ft, self.weights1)
        out_ft = torch.zeros(B, H, E, L // 2 + 1, device=xq.device, dtype=torch.cfloat)
        for i, j in enumerate(self.index_q):
            out_ft[:, :, :, j] = xqkvw[:, :, :, i]
        
        # 返回时域
        out = torch.fft.irfft(out_ft / self.in_channels / self.out_channels, n=xq.size(-1))
        return (out, None)

2. 模型

class FEDformer(BaseWindows):
    """ FEDformer

    The FEDformer model tackles the challenge of finding reliable dependencies on intricate temporal patterns of long-horizon forecasting.

    The architecture has the following distinctive features:
    - In-built progressive decomposition in trend and seasonal components based on a moving average filter.
    - Frequency Enhanced Block and Frequency Enhanced Attention to perform attention in the sparse representation on basis such as Fourier transform.
    - Classic encoder-decoder proposed by Vaswani et al. (2017) with a multi-head attention mechanism.

    The FEDformer model utilizes a three-component approach to define its embedding:
    - It employs encoded autoregressive features obtained from a convolution network.
    - Absolute positional embeddings obtained from calendar features are utilized.

    *Parameters:*<br>
    `h`: int, forecast horizon.<br>
    `input_size`: int, maximum sequence length for truncated train backpropagation. Default -1 uses all history.<br>
    `futr_exog_list`: str list, future exogenous columns.<br>
    `hist_exog_list`: str list, historic exogenous columns.<br>
    `stat_exog_list`: str list, static exogenous columns.<br>
    `decoder_input_size_multiplier`: float = 0.5, .<br>
    `version`: str = 'Fourier', version of the model.<br>
    `modes`: int = 64, number of modes for the Fourier block.<br>
    `mode_select`: str = 'random', method to select the modes for the Fourier block.<br>
    `hidden_size`: int=128, units of embeddings and encoders.<br>
    `dropout`: float (0, 1), dropout throughout Autoformer architecture.<br>
    `n_head`: int=8, controls number of multi-head's attention.<br>
    `conv_hidden_size`: int=32, channels of the convolutional encoder.<br>
    `activation`: str=`GELU`, activation from ['ReLU', 'Softplus', 'Tanh', 'SELU', 'LeakyReLU', 'PReLU', 'Sigmoid', 'GELU'].<br>
    `encoder_layers`: int=2, number of layers for the TCN encoder.<br>
    `decoder_layers`: int=1, number of layers for the MLP decoder.<br>
    `MovingAvg_window`: int=25, window size for the moving average filter.<br>
    `loss`: PyTorch module, instantiated train loss class from [losses collection](https://nixtla.github.io/neuralforecast/losses.pytorch.html).<br>
    `valid_loss`: PyTorch module, instantiated validation loss class from [losses collection](https://nixtla.github.io/neuralforecast/losses.pytorch.html).<br>
    `max_steps`: int=1000, maximum number of training steps.<br>
    `learning_rate`: float=1e-3, Learning rate between (0, 1).<br>
    `num_lr_decays`: int=-1, Number of learning rate decays, evenly distributed across max_steps.<br>
    `early_stop_patience_steps`: int=-1, Number of validation iterations before early stopping.<br>
    `val_check_steps`: int=100, Number of training steps between every validation loss check.<br>
    `batch_size`: int=32, number of different series in each batch.<br>
    `valid_batch_size`: int=None, number of different series in each validation and test batch, if None uses batch_size.<br>
    `windows_batch_size`: int=1024, number of windows to sample in each training batch, default uses all.<br>
    `inference_windows_batch_size`: int=1024, number of windows to sample in each inference batch.<br>
    `start_padding_enabled`: bool=False, if True, the model will pad the time series with zeros at the beginning, by input size.<br>
    `scaler_type`: str='robust', type of scaler for temporal inputs normalization see [temporal scalers](https://nixtla.github.io/neuralforecast/common.scalers.html).<br>
    `random_seed`: int=1, random_seed for pytorch initializer and numpy generators.<br>
    `num_workers_loader`: int=os.cpu_count(), workers to be used by `TimeSeriesDataLoader`.<br>
    `drop_last_loader`: bool=False, if True `TimeSeriesDataLoader` drops last non-full batch.<br>
    `alias`: str, optional,  Custom name of the model.<br>
    `optimizer`: Subclass of 'torch.optim.Optimizer', optional, user specified optimizer instead of the default choice (Adam).<br>
    `optimizer_kwargs`: dict, optional, list of parameters used by the user specified `optimizer`.<br>
    `lr_scheduler`: Subclass of 'torch.optim.lr_scheduler.LRScheduler', optional, user specified lr_scheduler instead of the default choice (StepLR).<br>
    `lr_scheduler_kwargs`: dict, optional, list of parameters used by the user specified `lr_scheduler`.<br>
    `**trainer_kwargs`: int,  keyword trainer arguments inherited from [PyTorch Lighning's trainer](https://pytorch-lightning.readthedocs.io/en/stable/api/pytorch_lightning.trainer.trainer.Trainer.html?highlight=trainer).<br>

    """
    # 类属性
    SAMPLING_TYPE = 'windows'
    EXOGENOUS_FUTR = True
    EXOGENOUS_HIST = False
    EXOGENOUS_STAT = False

    def __init__(self,
                 h: int, 
                 input_size: int,
                 stat_exog_list = None,
                 hist_exog_list = None,
                 futr_exog_list = None,
                 decoder_input_size_multiplier: float = 0.5,
                 version: str = 'Fourier',
                 modes: int = 64,
                 mode_select: str = 'random',
                 hidden_size: int = 128, 
                 dropout: float = 0.05,
                 n_head: int = 8,
                 conv_hidden_size: int = 32,
                 activation: str = 'gelu',
                 encoder_layers: int = 2, 
                 decoder_layers: int = 1,
                 MovingAvg_window: int = 25,
                 loss = MAE(),
                 valid_loss = None,
                 max_steps: int = 5000,
                 learning_rate: float = 1e-4,
                 num_lr_decays: int = -1,
                 early_stop_patience_steps: int =-1,
                 start_padding_enabled = False,
                 val_check_steps: int = 100,
                 batch_size: int = 32,
                 valid_batch_size: Optional[int] = None,
                 windows_batch_size = 1024,
                 inference_windows_batch_size = 1024,
                 step_size: int = 1,
                 scaler_type: str = 'identity',
                 random_seed: int = 1,
                 num_workers_loader: int = 0,
                 drop_last_loader: bool = False,
                 optimizer=None,
                 optimizer_kwargs=None,
                 lr_scheduler = None,
                 lr_scheduler_kwargs = None,
                 **trainer_kwargs):
        super(FEDformer, self).__init__(h=h,
                                       input_size=input_size,
                                       hist_exog_list=hist_exog_list,
                                       stat_exog_list=stat_exog_list,
                                       futr_exog_list = futr_exog_list,
                                       loss=loss,
                                       valid_loss=valid_loss,
                                       max_steps=max_steps,
                                       learning_rate=learning_rate,
                                       num_lr_decays=num_lr_decays,
                                       early_stop_patience_steps=early_stop_patience_steps,
                                       val_check_steps=val_check_steps,
                                       batch_size=batch_size,
                                       windows_batch_size=windows_batch_size,
                                       valid_batch_size=valid_batch_size,
                                       inference_windows_batch_size=inference_windows_batch_size,
                                       start_padding_enabled=start_padding_enabled,
                                       step_size=step_size,
                                       scaler_type=scaler_type,
                                       num_workers_loader=num_workers_loader,
                                       drop_last_loader=drop_last_loader,
                                       random_seed=random_seed,
                                       optimizer=optimizer,
                                       optimizer_kwargs=optimizer_kwargs,
                                       lr_scheduler=lr_scheduler,
                                       lr_scheduler_kwargs=lr_scheduler_kwargs,                                    
                                       **trainer_kwargs)
        # 建筑
        self.label_len = int(np.ceil(input_size * decoder_input_size_multiplier))
        if (self.label_len >= input_size) or (self.label_len <= 0):
            raise Exception(f'Check decoder_input_size_multiplier={decoder_input_size_multiplier}, range (0,1)')

        if activation not in ['relu', 'gelu']:
            raise Exception(f'Check activation={activation}')
        
        if n_head != 8:
            raise Exception('n_head must be 8')
        
        if version not in ['Fourier']:
            raise Exception('Only Fourier version is supported currently.')

        self.c_out = self.loss.outputsize_multiplier
        self.output_attention = False
        self.enc_in = 1 
        self.dec_in = 1
        
        self.decomp = SeriesDecomp(MovingAvg_window)

        # 嵌入
        self.enc_embedding = DataEmbedding(c_in=self.enc_in,
                                           exog_input_size=self.futr_exog_size,
                                           hidden_size=hidden_size, 
                                           pos_embedding=False,
                                           dropout=dropout)
        self.dec_embedding = DataEmbedding(self.dec_in,
                                           exog_input_size=self.futr_exog_size,
                                           hidden_size=hidden_size, 
                                           pos_embedding=False,
                                           dropout=dropout)

        encoder_self_att = FourierBlock(in_channels=hidden_size,
                                        out_channels=hidden_size,
                                        seq_len=input_size,
                                        modes=modes,
                                        mode_select_method=mode_select)
        decoder_self_att = FourierBlock(in_channels=hidden_size,
                                        out_channels=hidden_size,
                                        seq_len=input_size//2+self.h,
                                        modes=modes,
                                        mode_select_method=mode_select)
        decoder_cross_att = FourierCrossAttention(in_channels=hidden_size,
                                                    out_channels=hidden_size,
                                                    seq_len_q=input_size//2+self.h,
                                                    seq_len_kv=input_size,
                                                    modes=modes,
                                                    mode_select_method=mode_select)

        self.encoder = Encoder(
            [
                EncoderLayer(
                    AutoCorrelationLayer(
                        encoder_self_att,
                        hidden_size, n_head),

                    hidden_size=hidden_size,
                    conv_hidden_size=conv_hidden_size,
                    MovingAvg=MovingAvg_window,
                    dropout=dropout,
                    activation=activation
                ) for l in range(encoder_layers)
            ],
            norm_layer=LayerNorm(hidden_size)
        )
        # 解码器
        self.decoder = Decoder(
            [
                DecoderLayer(
                    AutoCorrelationLayer(
                        decoder_self_att,
                        hidden_size, n_head),
                    AutoCorrelationLayer(
                        decoder_cross_att,
                        hidden_size, n_head),
                    hidden_size=hidden_size,
                    c_out=self.c_out,
                    conv_hidden_size=conv_hidden_size,
                    MovingAvg=MovingAvg_window,
                    dropout=dropout,
                    activation=activation,
                )
                for l in range(decoder_layers)
            ],
            norm_layer=LayerNorm(hidden_size),
            projection=nn.Linear(hidden_size, self.c_out, bias=True)
        )

    def forward(self, windows_batch):
        # 解析Windows批处理文件
        insample_y    = windows_batch['insample_y']
        #insample_mask = windows_batch['insample_mask']
        #hist_exog     = windows_batch['hist_exog']
        #stat_exog     = windows_batch['stat_exog']
        futr_exog     = windows_batch['futr_exog']

        # 解析输入
        insample_y = insample_y.unsqueeze(-1) # [Ws,L,1]
        if self.futr_exog_size > 0:
            x_mark_enc = futr_exog[:,:self.input_size,:]
            x_mark_dec = futr_exog[:,-(self.label_len+self.h):,:]
        else:
            x_mark_enc = None
            x_mark_dec = None

        x_dec = torch.zeros(size=(len(insample_y),self.h, self.dec_in), device=insample_y.device)
        x_dec = torch.cat([insample_y[:,-self.label_len:,:], x_dec], dim=1)
                
        # 分解初始化
        mean = torch.mean(insample_y, dim=1).unsqueeze(1).repeat(1, self.h, 1)
        zeros = torch.zeros([x_dec.shape[0], self.h, x_dec.shape[2]], device=insample_y.device)
        seasonal_init, trend_init = self.decomp(insample_y)
        # 解码器输入
        trend_init = torch.cat([trend_init[:, -self.label_len:, :], mean], dim=1)
        seasonal_init = torch.cat([seasonal_init[:, -self.label_len:, :], zeros], dim=1)
        # 编码
        enc_out = self.enc_embedding(insample_y, x_mark_enc)
        enc_out, attns = self.encoder(enc_out, attn_mask=None)
        # 十二月
        dec_out = self.dec_embedding(seasonal_init, x_mark_dec)
        seasonal_part, trend_part = self.decoder(dec_out, enc_out, x_mask=None, cross_mask=None,
                                                 trend=trend_init)
        # 最终
        dec_out = trend_part + seasonal_part

        forecast = self.loss.domain_map(dec_out[:, -self.h:])
        return forecast
import pandas as pd
import matplotlib.pyplot as plt

from neuralforecast import NeuralForecast
from neuralforecast.models import FEDformer
from neuralforecast.utils import AirPassengersPanel, augment_calendar_df

AirPassengersPanel, calendar_cols = augment_calendar_df(df=AirPassengersPanel, freq='M')

Y_train_df = AirPassengersPanel[AirPassengersPanel.ds<AirPassengersPanel['ds'].values[-12]] # 132次列车
Y_test_df = AirPassengersPanel[AirPassengersPanel.ds>=AirPassengersPanel['ds'].values[-12]].reset_index(drop=True) # 12项测试
model = FEDformer(h=12,
                 input_size=24,
                 modes=64,
                 hidden_size=64,
                 conv_hidden_size=128,
                 n_head=8,
                 loss=MAE(),
                 futr_exog_list=calendar_cols,
                 scaler_type='robust',
                 learning_rate=1e-3,
                 max_steps=500,
                 batch_size=2,
                 windows_batch_size=32,
                 val_check_steps=50,
                 early_stop_patience_steps=2)

nf = NeuralForecast(
    models=[model],
    freq='M',
)
nf.fit(df=Y_train_df, static_df=None, val_size=12)
forecasts = nf.predict(futr_df=Y_test_df)

Y_hat_df = forecasts.reset_index(drop=False).drop(columns=['unique_id','ds'])
plot_df = pd.concat([Y_test_df, Y_hat_df], axis=1)
plot_df = pd.concat([Y_train_df, plot_df])

if model.loss.is_distribution_output:
    plot_df = plot_df[plot_df.unique_id=='Airline1'].drop('unique_id', axis=1)
    plt.plot(plot_df['ds'], plot_df['y'], c='black', label='True')
    plt.plot(plot_df['ds'], plot_df['FEDformer-median'], c='blue', label='median')
    plt.fill_between(x=plot_df['ds'][-12:], 
                    y1=plot_df['FEDformer-lo-90'][-12:].values, 
                    y2=plot_df['FEDformer-hi-90'][-12:].values,
                    alpha=0.4, label='level 90')
    plt.grid()
    plt.legend()
    plt.plot()
else:
    plot_df = plot_df[plot_df.unique_id=='Airline1'].drop('unique_id', axis=1)
    plt.plot(plot_df['ds'], plot_df['y'], c='black', label='True')
    plt.plot(plot_df['ds'], plot_df['FEDformer'], c='blue', label='Forecast')
    plt.legend()
    plt.grid()

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