Fix sawtooth generation

diffsptk/functional.py

@@ -512,7 +512,13 @@ def entropy(p, out_format="nat"):
     return nn.Entropy._func(p, out_format=out_format)
 
 
-def excite(p, frame_period=80, voiced_region="pulse", unvoiced_region="gauss"):
+def excite(
+    p,
+    frame_period=80,
+    voiced_region="pulse",
+    unvoiced_region="gauss",
+    polarity="auto",
+):
     """Generate a simple excitation signal.
 
     Parameters
@@ -523,12 +529,16 @@ def excite(p, frame_period=80, voiced_region="pulse", unvoiced_region="gauss"):
     frame_period : int >= 1
         Frame period in samples, :math:`P`.
 
-    voiced_region : ['pulse', 'sinusoidal', 'sawtooth']
+    voiced_region : ['pulse', 'sinusoidal', 'sawtooth', 'inverted-sawtooth', 'triangle',
+                     'square']
         Value on voiced region.
 
     unvoiced_region : ['gauss', 'zeros']
         Value on unvoiced region.
 
+    polarity : ['auto', 'unipolar', 'bipolar']
+        Polarity.
+
     Returns
     -------
     out : Tensor [shape=(..., NxP)]
@@ -540,6 +550,7 @@ def excite(p, frame_period=80, voiced_region="pulse", unvoiced_region="gauss"):
         frame_period=frame_period,
         voiced_region=voiced_region,
         unvoiced_region=unvoiced_region,
+        polarity=polarity,
     )
 
 

diffsptk/modules/excite.py

@@ -32,24 +32,43 @@ class ExcitationGeneration(nn.Module):
     frame_period : int >= 1
         Frame period in samples, :math:`P`.
 
-    voiced_region : ['pulse', 'sinusoidal', 'sawtooth']
+    voiced_region : ['pulse', 'sinusoidal', 'sawtooth', 'inverted-sawtooth', 'triangle',
+                     'square']
         Value on voiced region.
 
     unvoiced_region : ['gauss', 'zeros']
         Value on unvoiced region.
 
+    polarity : ['auto', 'unipolar', 'bipolar']
+        Polarity.
+
     """
 
-    def __init__(self, frame_period, voiced_region="pulse", unvoiced_region="gauss"):
+    def __init__(
+        self,
+        frame_period,
+        voiced_region="pulse",
+        unvoiced_region="gauss",
+        polarity="auto",
+    ):
         super().__init__()
 
         assert 1 <= frame_period
-        assert voiced_region in ("pulse", "sinusoidal", "sawtooth")
+        assert voiced_region in (
+            "pulse",
+            "sinusoidal",
+            "sawtooth",
+            "inverted-sawtooth",
+            "triangle",
+            "square",
+        )
         assert unvoiced_region in ("gauss", "zeros")
+        assert polarity in ("auto", "unipolar", "bipolar")
 
         self.frame_period = frame_period
         self.voiced_region = voiced_region
         self.unvoiced_region = unvoiced_region
+        self.polarity = polarity
 
     def forward(self, p):
         """Generate a simple excitation signal.
@@ -74,11 +93,15 @@ def forward(self, p):
 
         """
         return self._forward(
-            p, self.frame_period, self.voiced_region, self.unvoiced_region
+            p,
+            self.frame_period,
+            self.voiced_region,
+            self.unvoiced_region,
+            self.polarity,
         )
 
     @staticmethod
-    def _forward(p, frame_period, voiced_region, unvoiced_region):
+    def _forward(p, frame_period, voiced_region, unvoiced_region, polarity):
         # Make mask represents voiced region.
         base_mask = torch.clip(p, min=0, max=1)
         mask = torch.ne(base_mask, UNVOICED_SYMBOL)
@@ -106,16 +129,44 @@ def _forward(p, frame_period, voiced_region, unvoiced_region):
         phase = (s - bias).to(p.dtype)
 
         # Generate excitation signal using phase.
+        if polarity == "auto":
+            unipolar = voiced_region == "pulse"
+        else:
+            unipolar = polarity == "unipolar"
+        e = torch.zeros_like(p)
         if voiced_region == "pulse":
             r = torch.ceil(phase)
             r = F.pad(r, (1, 0))
             pulse_pos = torch.ge(torch.diff(r), 1)
-            e = torch.zeros_like(p)
-            e[pulse_pos] = torch.sqrt(p[pulse_pos])
+            if unipolar:
+                e[pulse_pos] = torch.sqrt(p[pulse_pos])
+            else:
+                raise RuntimeError
         elif voiced_region == "sinusoidal":
-            e = torch.sin(TWO_PI * phase)
+            if unipolar:
+                e[mask] = 0.5 * (1 - torch.cos(TWO_PI * phase[mask]))
+            else:
+                e[mask] = torch.sin(TWO_PI * phase[mask])
         elif voiced_region == "sawtooth":
-            e = torch.fmod(phase, 2) - 1
+            if unipolar:
+                e[mask] = torch.fmod(phase[mask], 1)
+            else:
+                e[mask] = 2 * torch.fmod(phase[mask], 1) - 1
+        elif voiced_region == "inverted-sawtooth":
+            if unipolar:
+                e[mask] = 1 - torch.fmod(phase[mask], 1)
+            else:
+                e[mask] = 1 - 2 * torch.fmod(phase[mask], 1)
+        elif voiced_region == "triangle":
+            if unipolar:
+                e[mask] = torch.abs(2 * torch.fmod(phase[mask] + 0.5, 1) - 1)
+            else:
+                e[mask] = 2 * torch.abs(2 * torch.fmod(phase[mask] + 1.75, 1) - 1) - 1
+        elif voiced_region == "square":
+            if unipolar:
+                e[mask] = torch.le(torch.fmod(phase[mask], 1), 0.5).to(e.dtype)
+            else:
+                e[mask] = 2 * torch.le(torch.fmod(phase[mask], 1), 0.5).to(e.dtype) - 1
         else:
             raise ValueError(f"voiced_region {voiced_region} is not supported.")
 

tests/test_excite.py

@@ -85,14 +85,21 @@ def compute_error(infile):
     U.call("rm -f excite.tmp?", get=False)
 
 
-@pytest.mark.parametrize("voiced_region", ["pulse", "sinusoidal", "sawtooth"])
-def test_waveform(voiced_region, P=80, verbose=False):
+@pytest.mark.parametrize(
+    "voiced_region",
+    ["pulse", "sinusoidal", "sawtooth", "inverted-sawtooth", "triangle", "square"],
+)
+@pytest.mark.parametrize("polarity", ["unipolar", "bipolar"])
+def test_waveform(voiced_region, polarity, P=80, verbose=False):
+    if voiced_region == "pulse" and polarity == "bipolar":
+        return
+
     excite = diffsptk.ExcitationGeneration(
-        P, voiced_region=voiced_region, unvoiced_region="zeros"
+        P, voiced_region=voiced_region, unvoiced_region="zeros", polarity=polarity
     )
     pitch = torch.from_numpy(
         U.call("x2x +sd tools/SPTK/asset/data.short | " f"pitch -s 16 -p {P} -o 0 -a 2")
     )
     e = excite(pitch)
     if verbose:
-        sf.write(f"excite_{voiced_region}.wav", e, 16000)
+        sf.write(f"excite_{voiced_region}_{polarity}.wav", e, 16000)