code: def find_event(interp_fn, sign0, t0, t1, event_fn, tol):
      with torch.no_grad():
          # Num iterations for the secant method until tolerance is within target.
          nitrs = torch.ceil(torch.log((t1 - t0) / tol) / math.log(2.0))
  
          for _ in range(nitrs.long()):
              t_mid = (t1 + t0) / 2.0
              y_mid = interp_fn(t_mid)
              sign_mid = torch.sign(event_fn(t_mid, y_mid))
              same_as_sign0 = sign0 == sign_mid
              t0 = torch.where(same_as_sign0, t_mid, t0)
              t1 = torch.where(same_as_sign0, t1, t_mid)
          event_t = (t0 + t1) / 2.0
  
      return event_t, interp_fn(event_t)
  
imports: import math
  import torch
label_desc: Use image node_id 1 for calling a global function with example usage: find_event(interp_fn, sign0, t0, t1, event_fn, tol) and returns: event_t,  interp_fn