Add helper functions to core.

PiperOrigin-RevId: 321609820
magenta · Jul 16, 2020 · 7afc8f0 · 7afc8f0
1 parent dd3fb52
commit 7afc8f0
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/ddsp/core.py b/ddsp/core.py
@@ -106,6 +106,11 @@ def soft_limit(x, x_min=0.0, x_max=1.0):
   return tf.nn.softplus(x) + x_min - tf.nn.softplus(x - (x_max - x_min))
 
 
+def gradient_reversal(x):
+  """Identity operation that reverses the gradient."""
+  return tf.stop_gradient(2.0 * x) - x
+
+
 # Unit Conversions -------------------------------------------------------------
 def midi_to_hz(notes: Number) -> Number:
   """TF-compatible midi_to_hz function."""