Update `generic.FFTransformer`

TTS/tts/layers/generic/transformer.py

@@ -15,17 +15,19 @@ class FFTransformer(nn.Module):
         self.norm1 = nn.LayerNorm(in_out_channels)
         self.norm2 = nn.LayerNorm(in_out_channels)
 
-        self.dropout = nn.Dropout(dropout_p)
+        self.dropout1 = nn.Dropout(dropout_p)
+        self.dropout2 = nn.Dropout(dropout_p)
 
     def forward(self, src, src_mask=None, src_key_padding_mask=None):
         """😦 ugly looking with all the transposing"""
         src = src.permute(2, 0, 1)
         src2, enc_align = self.self_attn(src, src, src, attn_mask=src_mask, key_padding_mask=src_key_padding_mask)
+        src = src + self.dropout1(src2)
         src = self.norm1(src + src2)
         # T x B x D -> B x D x T
         src = src.permute(1, 2, 0)
         src2 = self.conv2(F.relu(self.conv1(src)))
-        src2 = self.dropout(src2)
+        src2 = self.dropout2(src2)
         src = src + src2
         src = src.transpose(1, 2)
         src = self.norm2(src)
@@ -52,8 +54,8 @@ class FFTransformerBlock(nn.Module):
         """
         TODO: handle multi-speaker
         Shapes:
-            x: [B, C, T]
-            mask:  [B, 1, T] or [B, T]
+            - x: :math:`[B, C, T]`
+            - mask:  :math:`[B, 1, T] or [B, T]`
         """
         if mask is not None and mask.ndim == 3:
             mask = mask.squeeze(1)
@@ -65,3 +67,19 @@ class FFTransformerBlock(nn.Module):
             alignments.append(align.unsqueeze(1))
         alignments = torch.cat(alignments, 1)
         return x
+
+
+class FFTDurationPredictor:
+    def __init__(self, in_channels, hidden_channels, num_heads, num_layers, dropout_p=0.1, cond_channels=None):
+        self.fft = FFTransformerBlock(in_channels, num_heads, hidden_channels, num_layers, dropout_p)
+        self.proj = nn.Linear(in_channels, 1)
+
+    def forward(self, x, mask=None, g=None):
+        """
+        Shapes:
+            - x: :math:`[B, C, T]`
+            - mask:  :math:`[B, 1, T]`
+        """
+        x = self.fft(x, mask=mask)
+        x = self.proj(x)
+        return x