Add EPSILON to amp for numerical stability for division (#907)

SeldonIO · Nov 18, 2024 · 31d19a1 · 31d19a1
1 parent ecb3bcc
commit 31d19a1
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/alibi_detect/od/sr.py b/alibi_detect/od/sr.py
@@ -248,7 +248,8 @@ def saliency_map(self, X: np.ndarray) -> np.ndarray:
 
         fft = np.fft.fft(X)
         amp = np.abs(fft)
-        log_amp = np.log(amp)
+        # For numerical stability for division to prevent divide by zero being encountered add EPSILON
+        log_amp = np.log(amp + EPSILON)
         phase = np.angle(fft)
         # split spectrum into bias term and symmetric frequencies
         bias, sym_freq = log_amp[:1], log_amp[1:]