Testing by Comparison with the Spherically Symmetric Case

Simulating a spherical cloud   [l] Besides testing the individual components of the program as above some way also needs to be found by which the overall output of the program can be tested to show that the individual subroutines are working together correctly. This would also check that the general method being used is correct. The problem is that there are no analytical methods that can be used to solve the radiative transfer problem for a non-symmetric cloud. However, the 2-D version of the program can be used to roughly simulate a spherically symmetric cloud. Figure 5.8 shows one way of doing this. The figure shows a cross-section of the cylinders and disks, the rings are then filled in a manner that approximates a spherical cloud. If sufficient cylinders and disks are used the approximation will be quite good.