Add autoregressive neural network models

torchts/nn/models/autoreg.py

@@ -0,0 +1,33 @@
+import torch
+from torch import nn
+
+from torchts.nn.model import TimeSeriesModel
+
+
+class SimpleAR(TimeSeriesModel):
+    def __init__(self, p, bias=True, **kwargs):
+        super().__init__(**kwargs)
+        self.linear = nn.Linear(p, 1, bias=bias)
+
+    def forward(self, x):
+        return self.linear(x)
+
+
+class MultiAR(TimeSeriesModel):
+    def __init__(self, p, k, bias=True, **kwargs):
+        super().__init__(**kwargs)
+        self.p = p
+        self.k = k
+        self.layers = nn.ModuleList(nn.Linear(k, k, bias=False) for _ in range(p))
+        self.bias = nn.Parameter(torch.zeros(k)) if bias else None
+
+    def forward(self, x):
+        y = torch.zeros(x.shape[0], self.k)
+
+        for i in range(self.p):
+            y += self.layers[i](x[:, i, :])
+
+        if self.bias is not None:
+            y += self.bias
+
+        return y