code: def get_diffs(ptrms_vectors, ptrm_checks_vectors, ptrms_orig, checks_orig):
      
      ptrm_temps = numpy.array(ptrms_orig)[:,0]
      check_temps = numpy.array(checks_orig)[:,0]
      index = numpy.zeros(len(ptrm_temps))
      for num, temp in enumerate(ptrm_temps):
          if len(numpy.where(check_temps == temp)[0]):
              index[num] = numpy.where(check_temps == temp)[0][0]
          else:
              index[num] = float('nan')
      diffs = numpy.zeros((len(ptrms_vectors), 3))
      for num, ptrm in enumerate(ptrms_vectors):
          if numpy.isnan(index[num]):
              diffs[num] = numpy.array([0,0,0])
          else:
              diffs[num] = ptrm_checks_vectors[int(index[num])] - ptrm
      C = numpy.cumsum(diffs, 0)
      #print "diffs (should be same as to_sum"
      #print diffs
      #print "C (should be same as dpal_sum)"
      #print C
      return diffs, C
docs: input: ptrms_vectors, ptrm_checks_vectors, ptrms_orig, checks_orig
      output: vector diffs between original and ptrm check, C