Convergence of the temperature at cells near the xy-midplane of the disc model. The red line shows the results from the subiteration algorithm, and the crosses indicate the iterations where each grid was updated. The results of the full iterations, where all grids were updated at each iteration, are shown with the black lines without markers. The cells are approximately 0.625 AU, 1.25 AU, 6 AU, and 24 AU from the central star.