fix stft and istft in pyotrch 2.0.0

fix stft and istft in pyotrch 2.0.0
in pytorch 2.0.0 not support real output(stft)and real input(istft)

separate.py

@@ -392,7 +392,8 @@ def run_model(self, mix, is_ckpt=False, is_match_mix=False):
 
     def stft(self, x):
         x = x.reshape([-1, self.chunk_size])
-        x = torch.stft(x, n_fft=self.n_fft, hop_length=self.hop, window=self.window, center=True)
+        x = torch.stft(x, n_fft=self.n_fft, hop_length=self.hop, window=self.window, center=True,return_complex=True)
+        x=torch.view_as_real(x)
         x = x.permute([0,3,1,2])
         x = x.reshape([-1,2,2,self.n_bins,self.dim_t]).reshape([-1,self.dim_c,self.n_bins,self.dim_t])
         return x[:,:,:self.dim_f]
@@ -402,6 +403,8 @@ def istft(self, x, freq_pad=None):
         x = torch.cat([x, freq_pad], -2)
         x = x.reshape([-1,2,2,self.n_bins,self.dim_t]).reshape([-1,2,self.n_bins,self.dim_t])
         x = x.permute([0,2,3,1])
+        x=x.contiguous()
+        x=torch.view_as_complex(x)
         x = torch.istft(x, n_fft=self.n_fft, hop_length=self.hop, window=self.window, center=True)
         return x.reshape([-1,2,self.chunk_size])
 
@@ -936,4 +939,4 @@ def save_format(audio_path, save_format, mp3_bit_set):
         try:
             os.remove(audio_path)
         except Exception as e:
-            print(e)
+            print(e)