text: '''
  Created on 2020-11-03 10:40:32
  Last modified on 2020-11-03 15:20:55
  
  @author: L. F. Pereira (lfpereira@fe.up.pt))
  '''
  
  # imports
  
  # third-party
  import numpy as np
  
  # local library
  from .linalg import sqrtm
  
  
  # TODO: test using abaqus python
  
  # function definition
  
  def compute_small_strains_from_green(epsilon_green):
      '''
      Notes
      -----
      Assumes R=1.
      '''
      n = np.shape(epsilon_green)[0]
      identity = np.identity(n)
      def_grad = sqrtm(2 * epsilon_green + identity)
  
      return 1. / 2. * (def_grad + np.transpose(def_grad)) - identity
  