class_docstr: Instance of the pricing problem
docstr: Compute lower bound on higher-order solutions
code: def compute_LB(self, lambda1):
      """Compute lower bound on higher-order solutions"""
      Rp0 = self.rp.sum()
      if np.ndim(lambda1):
          self.LB = np.array([])
      else:
          self.LB = np.minimum(
              np.cumsum(np.sort(self.Rp)[::-1])[1:], Rp0
          )
          self.LB += np.sort(self.Rn)[-2::-1]
          self.LB -= lambda1 * np.arange(2, len(self.Rp) + 1)
          self.LB = self.v0 - self.LB
  
      # Lower bound specific to each singleton solution
      self.LB1 = self.v1 + self.Rp - Rp0 + lambda1
      if len(self.LB):
          self.LB1[self.LB1 < self.LB.min()] = self.LB.min()
  
file_path: AIX360/aix360/algorithms/rbm/beam_search.py
imports: import numpy
  import pandas
label_desc: Use image node_id 3 for calling the PricingInstance obj's underlying member method code with example usage: obj.compute_LB(lambda1) without return types