code: def _bstar_1effect(beta, alpha, yTBy, yTBX, yTBM, XTBX, XTBM, MTBM):
      
      from numpy_sugar import epsilon
      from numpy_sugar.linalg import dotd
      from numpy import sum
  
      r = full(MTBM[0].shape[0], yTBy)
      r -= 2 * add.reduce([dot(i, beta) for i in yTBX])
      r -= 2 * add.reduce([i * alpha for i in yTBM])
      r += add.reduce([dotd(beta.T, dot(i, beta)) for i in XTBX])
      r += add.reduce([dotd(beta.T, i * alpha) for i in XTBM])
      r += add.reduce([sum(alpha * i * beta, axis=0) for i in XTBM])
      r += add.reduce([alpha * i.ravel() * alpha for i in MTBM])
      return clip(r, epsilon.tiny, inf)
docs: Same as :func:`_bstar_set` but for single-effect.