misc improvement

src/model.py

@@ -84,7 +84,7 @@ def __init__(self, config, layer_id):
         self.time_gamma = nn.Parameter(torch.ones(config.ctx_len, 1))
         self.register_buffer("mask", torch.tril(torch.ones(config.ctx_len, config.ctx_len)))
 
-        self.time_shift = nn.ZeroPad2d((0,0,1,0))
+        self.time_shift = nn.ZeroPad2d((0,0,1,-1))
 
         self.key = nn.Linear(config.n_embd, config.n_attn)
         self.value = nn.Linear(config.n_embd, config.n_attn)
@@ -110,15 +110,15 @@ def forward(self, x):
         self.mask = self.mask[:T, :T]
         w = w.masked_fill(self.mask == 0, 0)
 
-        x = torch.cat([self.time_shift(x)[:, :-1, :C//2], x[:, :, C//2:]], dim = -1)
+        x = torch.cat([self.time_shift(x[:, :, :C//2]), x[:, :, C//2:]], dim = -1)
         if hasattr(self, 'tiny_att'):
             tiny_att = self.tiny_att(x, self.mask)
 
         k = self.key(x)
         v = self.value(x)
         r = self.receptance(x)
 
-        k = torch.clamp(k, max=30) # clamp extreme values. e^30 = 10^13
+        k = torch.clamp(k, max=30, min=-60) # clamp extreme values. e^30 = 10^13
         k = torch.exp(k)
         sum_k = torch.cumsum(k, dim=1)
 
@@ -138,7 +138,7 @@ class RWKV_ChannelMix(nn.Module):
     def __init__(self, config, layer_id):
         super().__init__()
         self.layer_id = layer_id
-        self.time_shift = nn.ZeroPad2d((0,0,1,0))
+        self.time_shift = nn.ZeroPad2d((0,0,1,-1))
 
         hidden_sz = 5 * config.n_ffn // 2 # can use smaller hidden_sz because of receptance gating
         self.key = nn.Linear(config.n_embd, hidden_sz)
@@ -152,7 +152,7 @@ def __init__(self, config, layer_id):
     def forward(self, x):
         B, T, C = x.size()
 
-        x = torch.cat([self.time_shift(x)[:, :-1, :C//2], x[:, :, C//2:]], dim = -1)
+        x = torch.cat([self.time_shift(x[:, :, :C//2]), x[:, :, C//2:]], dim = -1)
         k = self.key(x)
         v = self.value(x)
         r = self.receptance(x)
@@ -235,7 +235,7 @@ def __init__(self, config, layer_id, time_shift = False):
         self.head_size = config.n_attn // config.n_head
 
         if time_shift:
-            self.time_shift = nn.ZeroPad2d((0,0,1,0))
+            self.time_shift = nn.ZeroPad2d((0,0,1,-1))
 
         self.query = nn.Linear(config.n_embd, config.n_attn)
         self.key = nn.Linear(config.n_embd, config.n_attn)
@@ -252,7 +252,7 @@ def forward(self, x):
         B, T, C = x.size()
 
         if hasattr(self, 'time_shift'):
-            x = torch.cat([self.time_shift(x)[:, :-1, :C//2], x[:, :, C//2:]], dim = -1)
+            x = torch.cat([self.time_shift(x[:, :, :C//2]), x[:, :, C//2:]], dim = -1)
 
         q = self.query(x).view(B, T, self.n_head, self.head_size).transpose(1, 2)       # (B, T, C) -> (B, nh, T, hs)
         k = self.key(x).view(B, T, self.n_head, self.head_size).transpose(1, 2)         # (B, T, C) -> (B, nh, T, hs)
@@ -281,7 +281,7 @@ def __init__(self, config, layer_id, time_shift = False):
         self.layer_id = layer_id
 
         if time_shift:
-            self.time_shift = nn.ZeroPad2d((0,0,1,0))
+            self.time_shift = nn.ZeroPad2d((0,0,1,-1))
 
         hidden_sz = 3 * config.n_ffn
         self.key = nn.Linear(config.n_embd, hidden_sz)
@@ -291,7 +291,7 @@ def __init__(self, config, layer_id, time_shift = False):
     def forward(self, x):
         B, T, C = x.size()
         if hasattr(self, 'time_shift'):
-            x = torch.cat([self.time_shift(x)[:, :-1, :C//2], x[:, :, C//2:]], dim = -1)
+            x = torch.cat([self.time_shift(x[:, :, :C//2]), x[:, :, C//2:]], dim = -1)
 
         k = self.key(x)
         v = self.value(x)        
@@ -317,7 +317,7 @@ def __init__(self, config, layer_id):
         self.time_gamma = nn.Parameter(torch.ones(config.ctx_len, 1))
         self.register_buffer("mask", torch.tril(torch.ones(config.ctx_len, config.ctx_len)))
 
-        self.time_shift = nn.ZeroPad2d((0,0,1,0))
+        self.time_shift = nn.ZeroPad2d((0,0,1,-1))
         self.query = nn.Linear(config.n_embd, config.n_attn)
         self.key = nn.Linear(config.n_embd, config.n_attn)
         self.value = nn.Linear(config.n_embd, config.n_attn)
@@ -338,7 +338,7 @@ def forward(self, x):
         w = w[:, :, TT-1:] # w is now a circulant matrix
         w = w[:, :T, :T] * self.time_alpha[:, :, :T] * self.time_beta[:, :T, :]
 
-        x = torch.cat([self.time_shift(x)[:, :-1, :C//2], x[:, :, C//2:]], dim = -1)    # time-shift mixing
+        x = torch.cat([self.time_shift(x[:, :, :C//2]), x[:, :, C//2:]], dim = -1)      # time-shift mixing
         q = self.query(x).view(B, T, self.n_head, self.head_size).transpose(1, 2)       # (B, T, C) -> (B, nh, T, hs)
         k = self.key(x).view(B, T, self.n_head, self.head_size).transpose(1, 2)         # (B, T, C) -> (B, nh, T, hs)
         v = self.value(x).view(B, T, self.n_head, self.head_size).transpose(1, 2)       # (B, T, C) -> (B, nh, T, hs)