code: def compute(self, egocentricLocation):
      
      offsetInCellFields = (np.matmul(self.rotationMatrix, egocentricLocation) *
                            self.cellFieldsPerUnitDistance)
  
      np.mod(offsetInCellFields, self.cellDimensions, out=offsetInCellFields)
      self.activeCells = np.unique(
        np.ravel_multi_index(np.floor(offsetInCellFields).T.astype('int'),
                             self.cellDimensions))
docs: Compute the new active cells from the given "sensor location relative to
      body" vector.
  
      @param egocentricLocation (pair of floats)
      [di, dj] offset of the sensor from the body.