support rope

Author: Mddct

wenet/transformer/attention.py

@@ -20,6 +20,7 @@
 
 import torch
 from torch import nn
+from wenet.transformer.embedding import apply_rotary_emb
 
 from wenet.utils.common import get_dtype_min
 
@@ -424,3 +425,101 @@ def forward(
                 query.size(0), -1,
                 self.h * self.d_k))  # (batch, time1, d_model)
             return self.linear_out(output), new_cache
+
+
+class RopeMultiHeadedAttention(MultiHeadedAttention):
+
+    def __init__(self,
+                 n_head: int,
+                 n_feat: int,
+                 dropout_rate: float,
+                 key_bias: bool = True,
+                 use_sdpa: bool = False,
+                 bias: bool = True,
+                 n_kv_head: Optional[int] = None,
+                 head_dim: Optional[int] = None):
+        super().__init__(n_head, n_feat, dropout_rate, key_bias, use_sdpa,
+                         bias, n_kv_head, head_dim)
+
+    def forward(
+        self,
+        query: torch.Tensor,
+        key: torch.Tensor,
+        value: torch.Tensor,
+        mask: torch.Tensor = torch.ones((0, 0, 0), dtype=torch.bool),
+        pos_emb: torch.Tensor = torch.empty(0),
+        cache: torch.Tensor = torch.zeros((0, 0, 0, 0))
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """Compute scaled dot product attention.
+
+        Args:
+            query (torch.Tensor): Query tensor (#batch, time1, size).
+            key (torch.Tensor): Key tensor (#batch, time2, size).
+            value (torch.Tensor): Value tensor (#batch, time2, size).
+            mask (torch.Tensor): Mask tensor (#batch, 1, time2) or
+                (#batch, time1, time2).
+                1.When applying cross attention between decoder and encoder,
+                the batch padding mask for input is in (#batch, 1, T) shape.
+                2.When applying self attention of encoder,
+                the mask is in (#batch, T, T)  shape.
+                3.When applying self attention of decoder,
+                the mask is in (#batch, L, L)  shape.
+                4.If the different position in decoder see different block
+                of the encoder, such as Mocha, the passed in mask could be
+                in (#batch, L, T) shape. But there is no such case in current
+                Wenet.
+            cache (torch.Tensor): Cache tensor (1, head, cache_t, d_k * 2),
+                where `cache_t == chunk_size * num_decoding_left_chunks`
+                and `head * d_k == size`
+
+
+        Returns:
+            torch.Tensor: Output tensor (#batch, time1, d_model).
+            torch.Tensor: Cache tensor (1, head, cache_t + time1, d_k * 2)
+                where `cache_t == chunk_size * num_decoding_left_chunks`
+                and `head * d_k == size`
+
+        """
+        q, k, v = self.forward_qkv(query, key, value)
+        # see above
+        if cache.size(0) > 0:
+            key_cache, value_cache = torch.split(cache,
+                                                 cache.size(-1) // 2,
+                                                 dim=-1)
+            k = torch.cat([key_cache, k], dim=2)
+            v = torch.cat([value_cache, v], dim=2)
+
+        # NOTE(Mddct): In order to make the code easier to read,
+        #    these two lines are not placed in MultiHeadedAttention.
+        q = apply_rotary_emb(q, freqs_cis=pos_emb)
+        k = apply_rotary_emb(k, freqs_cis=pos_emb)
+
+        new_cache = torch.cat((k, v), dim=-1)
+        if self.h_kv != self.h:
+            k = torch.repeat_interleave(
+                k,
+                self.h // self.h_kv,
+                dim=1,
+            )
+            v = torch.repeat_interleave(
+                v,
+                self.h // self.h_kv,
+                dim=1,
+            )
+
+        if not self.use_sdpa:
+            scores = torch.matmul(q, k.transpose(-2, -1)) / math.sqrt(self.d_k)
+            return self.forward_attention(v, scores, mask), new_cache
+        else:
+            output = torch.nn.functional.scaled_dot_product_attention(
+                q,
+                k,
+                v,
+                attn_mask=mask.unsqueeze(1),
+                dropout_p=self.dropout_rate,
+                scale=1 / math.sqrt(self.d_k),
+            )
+            output = (output.transpose(1, 2).contiguous().view(
+                query.size(0), -1,
+                self.h * self.d_k))  # (batch, time1, d_model)
+            return self.linear_out(output), new_cache

wenet/transformer/embedding.py

@@ -178,7 +178,7 @@ class NoPositionalEncoding(torch.nn.Module):
     """ No position encoding
     """
 
-    def __init__(self, d_model: int, dropout_rate: float):
+    def __init__(self, d_model: int, dropout_rate: float, *args):
         super().__init__()
         self.d_model = d_model
         self.dropout = torch.nn.Dropout(p=dropout_rate)
@@ -195,3 +195,62 @@ def forward(self,
     def position_encoding(self, offset: Union[int, torch.Tensor],
                           size: int) -> torch.Tensor:
         return torch.zeros(1, size, self.d_model)
+
+
+# copy from:https://github.com/google/gemma_pytorch/blob/main/gemma/model.py#L84
+def precompute_freqs_cis(dim: int,
+                         end: int,
+                         theta: float = 10000.0) -> torch.Tensor:
+    """Precomputes the frequency cis."""
+    freqs = 1.0 / (theta**(torch.arange(0, dim, 2)[:(dim // 2)].float() / dim))
+    t = torch.arange(end, device=freqs.device)
+    freqs = torch.outer(t, freqs).float()
+    freqs_cis = torch.polar(torch.ones_like(freqs), freqs)  # complex64
+    return freqs_cis
+
+
+# copy from:https://github.com/google/gemma_pytorch/blob/main/gemma/model.py#L95
+def apply_rotary_emb(x: torch.Tensor, freqs_cis: torch.Tensor) -> torch.Tensor:
+    """Applies the rotary embedding to the query and key tensors."""
+    x_ = torch.view_as_complex(
+        torch.stack(torch.chunk(x.transpose(1, 2).float(), 2, dim=-1), dim=-1))
+    x_out = torch.view_as_real(x_ * freqs_cis).type_as(x)
+    x_out = torch.cat(torch.chunk(x_out, 2, dim=-1), dim=-2)
+    x_out = x_out.reshape(x_out.shape[0], x_out.shape[1], x_out.shape[2],
+                          -1).transpose(1, 2)
+    return x_out
+
+
+class RopePositionalEncoding(PositionalEncoding):
+
+    def __init__(self,
+                 d_model: int,
+                 dropout_rate: float,
+                 max_len: int = 1500,
+                 rope_theta=10000.0):
+        super().__init__(d_model, dropout_rate=dropout_rate, max_len=max_len)
+        delattr(self, 'pe')
+        self.pe = precompute_freqs_cis(d_model, max_len * 2, rope_theta)
+        self.dropout_rate = dropout_rate
+
+    def forward(
+        self,
+        x: torch.Tensor,
+        offset: Union[int,
+                      torch.Tensor] = 0) -> Tuple[torch.Tensor, torch.Tensor]:
+
+        self.pe = self.pe.to(x.device)
+        pos_emb = self.position_encoding(offset, x.size(1), False)
+        # NOTE(Mddct): some model don't scale
+        # TODO(Mddct): fix
+        x = x * self.xscale
+        # NOTE(Mddct) dropout don't suuport complex float for pos_emb
+        return self.dropout(x), self.dropout_complex(pos_emb)
+
+    def dropout_complex(self, x):
+        mask = torch.nn.functional.dropout(
+            torch.ones_like(x.real),
+            training=self.training,
+            p=self.dropout_rate,
+        )
+        return x * mask

wenet/utils/class_utils.py

@@ -21,11 +21,13 @@
 from wenet.squeezeformer.subsampling import DepthwiseConv2dSubsampling4
 from wenet.transformer.embedding import (PositionalEncoding,
                                          RelPositionalEncoding,
+                                         RopePositionalEncoding,
                                          WhisperPositionalEncoding,
                                          LearnablePositionalEncoding,
                                          NoPositionalEncoding)
 from wenet.transformer.attention import (MultiHeadedAttention,
-                                         RelPositionMultiHeadedAttention)
+                                         RelPositionMultiHeadedAttention,
+                                         RopeMultiHeadedAttention)
 from wenet.efficient_conformer.attention import GroupedRelPositionMultiHeadedAttention
 
 WENET_ACTIVATION_CLASSES = {
@@ -63,12 +65,14 @@
     "abs_pos_whisper": WhisperPositionalEncoding,
     "embed_learnable_pe": LearnablePositionalEncoding,
     "abs_pos_paraformer": ParaformerPositinoalEncoding,
+    "rope": RopePositionalEncoding,
 }
 
 WENET_ATTENTION_CLASSES = {
     "selfattn": MultiHeadedAttention,
     "rel_selfattn": RelPositionMultiHeadedAttention,
     "grouped_rel_selfattn": GroupedRelPositionMultiHeadedAttention,
+    "rope_selfattn": RopeMultiHeadedAttention,
 }
 
 WENET_MLP_CLASSES = {