BMW: Add numpy_fast.py with clip, interp, and mean functions

common/numpy_fast.py

@@ -0,0 +1,19 @@
+def clip(x, lo, hi):
+  return max(lo, min(hi, x))
+
+def interp(x, xp, fp):
+  N = len(xp)
+
+  def get_interp(xv):
+    hi = 0
+    while hi < N and xv > xp[hi]:
+      hi += 1
+    low = hi - 1
+    return fp[-1] if hi == N and xv > xp[low] else (
+      fp[0] if hi == 0 else
+      (xv - xp[low]) * (fp[hi] - fp[low]) / (xp[hi] - xp[low]) + fp[low])
+
+  return [get_interp(v) for v in x] if hasattr(x, '__iter__') else get_interp(x)
+
+def mean(x):
+  return sum(x) / len(x)

opendbc_repo/opendbc/car/bmw/carcontroller.py

@@ -6,7 +6,7 @@
 from opendbc.car.interfaces import CarControllerBase
 from opendbc.can.packer import CANPacker
 from opendbc.car.common.conversions import Conversions as CV
-from common import numpy_fast as np
+import common.numpy_fast as np
 
 VisualAlert = car_capnp.CarControl.HUDControl.VisualAlert