Safe exp in parsing (#33640)

selfdrive/modeld/parse_model_outputs.py

@@ -1,17 +1,19 @@
 import numpy as np
 from openpilot.selfdrive.modeld.constants import ModelConstants
 
-def sigmoid(x):
+def safe_exp(x, out=None):
   # -11 is around 10**14, more causes float16 overflow
-  clipped_x = np.clip(x, -11, np.inf)
-  return 1. / (1. + np.exp(-clipped_x))
+  return np.exp(np.clip(x, -np.inf, 11), out=out)
+
+def sigmoid(x):
+  return 1. / (1. + safe_exp(-x))
 
 def softmax(x, axis=-1):
   x -= np.max(x, axis=axis, keepdims=True)
   if x.dtype == np.float32 or x.dtype == np.float64:
-    np.exp(x, out=x)
+    safe_exp(x, out=x)
   else:
-    x = np.exp(x)
+    x = safe_exp(x)
   x /= np.sum(x, axis=axis, keepdims=True)
   return x
 
@@ -46,7 +48,7 @@ def parse_mdn(self, name, outs, in_N=0, out_N=1, out_shape=None):
 
     n_values = (raw.shape[2] - out_N)//2
     pred_mu = raw[:,:,:n_values]
-    pred_std = np.exp(raw[:,:,n_values: 2*n_values])
+    pred_std = safe_exp(raw[:,:,n_values: 2*n_values])
 
     if in_N > 1:
       weights = np.zeros((raw.shape[0], in_N, out_N), dtype=raw.dtype)