Merge pull request #23 from awgu/pt2

Register `freqs_cis` as non-persistent buffer

model.py

@@ -195,7 +195,8 @@ class Transformer(nn.Module):
         self.tok_embeddings.weight = self.output.weight # https://paperswithcode.com/method/weight-tying
 
         # some useful precompute for the RoPE relative positional embeddings. TODO why * 2 here? confuse
-        self.freqs_cis = precompute_freqs_cis(self.params.dim // self.params.n_heads, self.params.max_seq_len * 2)
+        freqs_cis = precompute_freqs_cis(self.params.dim // self.params.n_heads, self.params.max_seq_len * 2)
+        self.register_buffer("freqs_cis", freqs_cis, persistent=False)
         
         # init all weights
         self.apply(self._init_weights)
@@ -215,7 +216,6 @@ class Transformer(nn.Module):
     def forward(self, tokens, targets=None):
         _bsz, seqlen = tokens.shape
         h = self.tok_embeddings(tokens)
-        self.freqs_cis = self.freqs_cis.to(h.device)
         freqs_cis = self.freqs_cis[:seqlen]
 
         for layer in self.layers: