text: """
  measure.py
  A python package for the MolSSI Software Summer School.
  
  Measures things
  """
  import numpy as np
  
  def calculate_distance(rA, rB):
      """Calculate the distance between points A and B.
  
      Parameters
      ----------
      rA : numpy array
          The x, y, z coordinates of point A
      rB : numpy array
          The x, y, z coordinates of point B
  
      Returns
      -------
      distance : float
          The distance between points A and B.
  
      Examples
      --------
      >>> r1= np.array([0, 0, 0])
      >>> r2= np.array([0, 0.1, 0])
      >>> calculate_distance(r1,r2)
      0.1
      """
      dist_vec = (rA-rB)
      distance = np.linalg.norm(dist_vec)
      return distance
  
  def calculate_angle(rA, rB, rC, degrees=False):
      """Calculate angle between points A, B, and C
  
      Parameters
      ----------
      rA : numpy array
          The x, y, z coordinates of point A
      rB : numpy array
          The x, y, z coordinates of point B
      degrees : bool, optional
          Return the calculated angle in degrees.
  
      Returns
      -------
      angle : float
          The distance between points A and B.
      """
      AB = rB - rA
      BC = rB - rC
  
      theta = np.arccos(np.dot(AB, BC) / (np.linalg.norm(AB)*np.linalg.norm(BC)))
  
  
      if degrees:
          return np.degrees(theta)
      else:
          return theta