Tutorials

In addition to the tests, we will here consider the general settings of the ASWNS code. These settings can be found in the file ASWNS.f90 and determine fundamental constants, but also the grid setup, or iteration details.

If you open ASWNS.f90, you will find the following parameters

• nr (integer) –> total number of radial grid points
• nth (integer) –> total number of angular grid points
• mls (integer) –> maximum number of employed Legendre polynomials for the expansion in theta
• rhalf (double) –> end of the inner radial grid/beginning of the outer grid
• rmax (double) –> end of outer (radial) grid
• planar_symmetry (logical) –> employing symmetry through neglecting odd harmonics
• qfactor (double) –> damping factor for the metric quantities during iteration
• abs_tol (double) –> tolerance when solution is considered to be converged
• verbose (logical) –> determines if the output is put on the screen
• wait_iters (integer) –> number of iterations before checking for convergence after hydro relaxation

And the following constants are used:

• nm (double) = 8.42335d-58 –> neutron mass given in Msun
• rhon (double) = 4.339d-4 –> nuclear saturation density given in Msun^-2
• km_to_msol (double) = 0.677218135d0 –> conversion from km to solar masses

While it isn't to be expected that you need to change the overall constants, it might be worth changing some of the iteration parameters. For this purpose, let us consider