code: def dostilt(s, bed_az, bed_dip):
      
      tau, Vdirs = doseigs(s)
      Vrot = []
      for evec in Vdirs:
          d, i = dotilt(evec[0], evec[1], bed_az, bed_dip)
          Vrot.append([d, i])
      s_rot = doeigs_s(tau, Vrot)
      return s_rot
docs: Rotates "s" tensor to stratigraphic coordinates
  
      Parameters
      __________
      s : [x11,x22,x33,x12,x23,x13] - the six tensor elements
      bed_az : bedding dip direction
      bed_dip :  bedding dip
  
      Return
      s_rot : [x11,x22,x33,x12,x23,x13] - after rotation