From 03d4ce829814b4a7f57235fda049351c524ba32b Mon Sep 17 00:00:00 2001
From: zhifu gao <zhifu.gzf@alibaba-inc.com>
Date: 星期五, 17 三月 2023 14:06:56 +0800
Subject: [PATCH] Merge branch 'main' into dev_xw

---
 funasr/modules/eend_ola/encoder.py |  133 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 133 insertions(+), 0 deletions(-)

diff --git a/funasr/modules/eend_ola/encoder.py b/funasr/modules/eend_ola/encoder.py
new file mode 100644
index 0000000..90a63f3
--- /dev/null
+++ b/funasr/modules/eend_ola/encoder.py
@@ -0,0 +1,133 @@
+import math
+
+import torch
+import torch.nn.functional as F
+from torch import nn
+
+
+class MultiHeadSelfAttention(nn.Module):
+    def __init__(self, n_units, h=8, dropout_rate=0.1):
+        super(MultiHeadSelfAttention, self).__init__()
+        self.linearQ = nn.Linear(n_units, n_units)
+        self.linearK = nn.Linear(n_units, n_units)
+        self.linearV = nn.Linear(n_units, n_units)
+        self.linearO = nn.Linear(n_units, n_units)
+        self.d_k = n_units // h
+        self.h = h
+        self.dropout = nn.Dropout(dropout_rate)
+
+    def __call__(self, x, batch_size, x_mask):
+        q = self.linearQ(x).view(batch_size, -1, self.h, self.d_k)
+        k = self.linearK(x).view(batch_size, -1, self.h, self.d_k)
+        v = self.linearV(x).view(batch_size, -1, self.h, self.d_k)
+        scores = torch.matmul(
+            q.permute(0, 2, 1, 3), k.permute(0, 2, 3, 1)) / math.sqrt(self.d_k)
+        if x_mask is not None:
+            x_mask = x_mask.unsqueeze(1)
+            scores = scores.masked_fill(x_mask == 0, -1e9)
+        self.att = F.softmax(scores, dim=3)
+        p_att = self.dropout(self.att)
+        x = torch.matmul(p_att, v.permute(0, 2, 1, 3))
+        x = x.permute(0, 2, 1, 3).contiguous().view(-1, self.h * self.d_k)
+        return self.linearO(x)
+
+
+class PositionwiseFeedForward(nn.Module):
+    def __init__(self, n_units, d_units, dropout_rate):
+        super(PositionwiseFeedForward, self).__init__()
+        self.linear1 = nn.Linear(n_units, d_units)
+        self.linear2 = nn.Linear(d_units, n_units)
+        self.dropout = nn.Dropout(dropout_rate)
+
+    def __call__(self, x):
+        return self.linear2(self.dropout(F.relu(self.linear1(x))))
+
+
+class PositionalEncoding(torch.nn.Module):
+    def __init__(self, d_model, dropout_rate, max_len=5000, reverse=False):
+        super(PositionalEncoding, self).__init__()
+        self.d_model = d_model
+        self.reverse = reverse
+        self.xscale = math.sqrt(self.d_model)
+        self.dropout = torch.nn.Dropout(p=dropout_rate)
+        self.pe = None
+        self.extend_pe(torch.tensor(0.0).expand(1, max_len))
+
+    def extend_pe(self, x):
+        if self.pe is not None:
+            if self.pe.size(1) >= x.size(1):
+                if self.pe.dtype != x.dtype or self.pe.device != x.device:
+                    self.pe = self.pe.to(dtype=x.dtype, device=x.device)
+                return
+        pe = torch.zeros(x.size(1), self.d_model)
+        if self.reverse:
+            position = torch.arange(
+                x.size(1) - 1, -1, -1.0, dtype=torch.float32
+            ).unsqueeze(1)
+        else:
+            position = torch.arange(0, x.size(1), dtype=torch.float32).unsqueeze(1)
+        div_term = torch.exp(
+            torch.arange(0, self.d_model, 2, dtype=torch.float32)
+            * -(math.log(10000.0) / self.d_model)
+        )
+        pe[:, 0::2] = torch.sin(position * div_term)
+        pe[:, 1::2] = torch.cos(position * div_term)
+        pe = pe.unsqueeze(0)
+        self.pe = pe.to(device=x.device, dtype=x.dtype)
+
+    def forward(self, x: torch.Tensor):
+        self.extend_pe(x)
+        x = x * self.xscale + self.pe[:, : x.size(1)]
+        return self.dropout(x)
+
+
+class EENDOLATransformerEncoder(nn.Module):
+    def __init__(self,
+                 idim: int,
+                 n_layers: int,
+                 n_units: int,
+                 e_units: int = 2048,
+                 h: int = 4,
+                 dropout_rate: float = 0.1,
+                 use_pos_emb: bool = False):
+        super(EENDOLATransformerEncoder, self).__init__()
+        self.lnorm_in = nn.LayerNorm(n_units)
+        self.n_layers = n_layers
+        self.dropout = nn.Dropout(dropout_rate)
+        for i in range(n_layers):
+            setattr(self, '{}{:d}'.format("lnorm1_", i),
+                    nn.LayerNorm(n_units))
+            setattr(self, '{}{:d}'.format("self_att_", i),
+                    MultiHeadSelfAttention(n_units, h))
+            setattr(self, '{}{:d}'.format("lnorm2_", i),
+                    nn.LayerNorm(n_units))
+            setattr(self, '{}{:d}'.format("ff_", i),
+                    PositionwiseFeedForward(n_units, e_units, dropout_rate))
+        self.lnorm_out = nn.LayerNorm(n_units)
+        if use_pos_emb:
+            self.pos_enc = torch.nn.Sequential(
+                torch.nn.Linear(idim, n_units),
+                torch.nn.LayerNorm(n_units),
+                torch.nn.Dropout(dropout_rate),
+                torch.nn.ReLU(),
+                PositionalEncoding(n_units, dropout_rate),
+            )
+        else:
+            self.linear_in = nn.Linear(idim, n_units)
+            self.pos_enc = None
+
+    def __call__(self, x, x_mask=None):
+        BT_size = x.shape[0] * x.shape[1]
+        if self.pos_enc is not None:
+            e = self.pos_enc(x)
+            e = e.view(BT_size, -1)
+        else:
+            e = self.linear_in(x.reshape(BT_size, -1))
+        for i in range(self.n_layers):
+            e = getattr(self, '{}{:d}'.format("lnorm1_", i))(e)
+            s = getattr(self, '{}{:d}'.format("self_att_", i))(e, x.shape[0], x_mask)
+            e = e + self.dropout(s)
+            e = getattr(self, '{}{:d}'.format("lnorm2_", i))(e)
+            s = getattr(self, '{}{:d}'.format("ff_", i))(e)
+            e = e + self.dropout(s)
+        return self.lnorm_out(e)

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