text: # Copyright (c) 2020 Institute for Quantum Computing, Baidu Inc. All Rights Reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  """
  main
  """
  
  import numpy
  
  from paddle_quantum.SSVQE.HGenerator import H_generator
  from paddle_quantum.SSVQE.Paddle_SSVQE import Paddle_SSVQE
  
  
  def main():
      N = 2
      H = H_generator(N)
  
      loss_components = Paddle_SSVQE(H)
  
      print('The estimated ground state energy is: ', loss_components[0].numpy())
      print('The theoretical ground state energy: ', numpy.linalg.eigh(H)[0][0])
  
      print('The estimated 1st excited state energy is: ', loss_components[1].numpy())
      print('The theoretical 1st excited state energy: ', numpy.linalg.eigh(H)[0][1])
  
      print('The estimated 2nd excited state energy is: ', loss_components[2].numpy())
      print('The theoretical 2nd excited state energy: ', numpy.linalg.eigh(H)[0][2])
  
      print('The estimated 3rd excited state energy is: ', loss_components[3].numpy())
      print('The theoretical 3rd excited state energy: ', numpy.linalg.eigh(H)[0][3])
  
  
  if __name__ == '__main__':
      main()
  