def sigmoid(c):
  return 1.0/(1.0 + np.exp(-c))
returns a unique id for this context
dataset/ETHPy150Open daeilkim/refinery/refinery/bnpy/bnpy-dev/bnpy/allocmodel/admix/OptimizerForHDPPE.py/sigmoid--crossover with--dataset/ETHPy150Open manahl/mdf/mdf/context.py/MDFContext.get_id