Updated comments for all new GR regression tests (including all black…

… hole magnetosphere tests for the general relativistic Maxwell equations, ultra-relativistic Euler tests, coupled fluid-Einstein tests in plane-symmetric spacetimes, and all test variants in the tetrad basis).

regression/rt_gr_bhl_spinning_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Bondi-Hoyle-Lyttleton accretion problem onto a non-static (Kerr) black hole, for the general relativistic Euler equations in the tetrad basis.
+// Input parameters describe wind accretion of a cold relativistic gas onto a spinning black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_bhl_static_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Bondi-Hoyle-Lyttleton accretion problem onto a static (Schwarzschild) black hole, for the general relativistic Euler equations in the tetrad basis.
+// Input parameters describe wind accretion of a cold relativistic gas onto a non-rotating black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_bz_monopole_fast.c

@@ -1,3 +1,10 @@
+// 2D Blandford-Znajek magnetosphere problem for a rapidly-rotating (Kerr) black hole, for the general relativistic Maxwell equations.
+// Input parameters describe a (purely radial) monopole magnetic field surrounding a rapidly-rotating black hole.
+// Based on the perturbative analytical solution for force-free electrodynamics presented in the article:
+// R. D. Blandford and R. L. Znajek (1977), "Electromagnetic extraction of energy from Kerr black holes",
+// Monthly Notices of the Royal Astronomical Society, Volume 179 (3): 433-456.
+// https://academic.oup.com/mnras/article/179/3/433/962905
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_bz_monopole_fast_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Blandford-Znajek magnetosphere problem for a rapidly-rotating (Kerr) black hole, for the general relativistic Maxwell equations in the tetrad basis.
+// Input parameters describe a (purely radial) monopole magnetic field surrounding a rapidly-rotating black hole.
+// Based on the perturbative analytical solution for force-free electrodynamics presented in the article:
+// R. D. Blandford and R. L. Znajek (1977), "Electromagnetic extraction of energy from Kerr black holes",
+// Monthly Notices of the Royal Astronomical Society, Volume 179 (3): 433-456.
+// https://academic.oup.com/mnras/article/179/3/433/962905
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_bz_monopole_slow.c

@@ -1,3 +1,10 @@
+// 2D Blandford-Znajek magnetosphere problem for a slowly-rotating (Kerr) black hole, for the general relativistic Maxwell equations.
+// Input parameters describe a (purely radial) monopole magnetic field surrounding a slowly-rotating black hole.
+// Based on the perturbative analytical solution for force-free electrodynamics presented in the article:
+// R. D. Blandford and R. L. Znajek (1977), "Electromagnetic extraction of energy from Kerr black holes",
+// Monthly Notices of the Royal Astronomical Society, Volume 179 (3): 433-456.
+// https://academic.oup.com/mnras/article/179/3/433/962905
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_bz_monopole_slow_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Blandford-Znajek magnetosphere problem for a slowly-rotating (Kerr) black hole, for the general relativistic Maxwell equations in the tetrad basis.
+// Input parameters describe a (purely radial) monopole magnetic field surrounding a slowly-rotating black hole.
+// Based on the perturbative analytical solution for force-free electrodynamics presented in the article:
+// R. D. Blandford and R. L. Znajek (1977), "Electromagnetic extraction of energy from Kerr black holes",
+// Monthly Notices of the Royal Astronomical Society, Volume 179 (3): 433-456.
+// https://academic.oup.com/mnras/article/179/3/433/962905
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_current_sheet.c

@@ -1,3 +1,9 @@
+// 1D current sheet Riemann problem for the general relativistic Maxwell equations.
+// Input parameters taken from the initial conditions in Section C3.2 (current sheet), from the article:
+// S. S. Komissarov (2004), "Electrodynamics of black hole magnetospheres",
+// Monthly Notices of the Royal Astronomical Society, Volume 350 (2): 427-448.
+// https://arxiv.org/abs/astro-ph/0402403
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_current_sheet_tetrad.c

@@ -1,3 +1,9 @@
+// 1D current sheet Riemann problem for the general relativistic Maxwell equations in the tetrad basis.
+// Input parameters taken from the initial conditions in Section C3.2 (current sheet), from the article:
+// S. S. Komissarov (2004), "Electrodynamics of black hole magnetospheres",
+// Monthly Notices of the Royal Astronomical Society, Volume 350 (2): 427-448.
+// https://arxiv.org/abs/astro-ph/0402403
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_einstein_plane_shock.c

@@ -1,3 +1,9 @@
+// Shock tube test on a plane-symmetric Gowdy spacetime for the coupled fluid-Einstein equations, assuming an ultra-relativistic equation of state.
+// Input parameters taken from the initial conditions in Section 9 (Riemann problem 1), from the article:
+// A. P. Barnes, P. G. Lefloch, B. G. Schmidt and J. M. Stewart (2004), "The Glimm scheme for perfect fluids on plane-symmetric Gowdy spacetimes",
+// Classical and Quantum Gravity, Volume 21 (22): 5043.
+// https://iopscience.iop.org/article/10.1088/0264-9381/21/22/003
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_mild_shock_tetrad.c

@@ -1,3 +1,9 @@
+// Mildly relativistic blast wave test for the general relativistic Euler equations in the tetrad basis.
+// Input parameters taken from the initial conditions in Section 4.1 (blast wave 1), from the article:
+// L. Del Zanna and N. Bucciantini (2002), "An efficient shock-cpaturing central-type scheme for multidimensional relativistic flows. I. Hydrodynamics",
+// Astronomy and Astrophysics, Volume 390 (3): 1177-1186.
+// https://arxiv.org/abs/astro-ph/0205290
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_bhl_spinning.c

@@ -1,3 +1,11 @@
+// 2D Bondi-Hoyle-Lyttleton ultra-relativistic accretion problem onto a non-static (Kerr) black hole, for the general relativistic Euler equations,
+// assuming a stiff equation of state.
+// Input parameters describe wind accretion of an ultra-relativistic gas onto a spinning black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_bhl_spinning_tetrad.c

@@ -1,3 +1,11 @@
+// 2D Bondi-Hoyle-Lyttleton ultra-relativistic accretion problem onto a non-static (Kerr) black hole, for the general relativistic Euler equations in the tetrad basis,
+// assuming a stiff equation of state.
+// Input parameters describe wind accretion of an ultra-relativistic gas onto a spinning black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_bhl_static.c

@@ -1,3 +1,11 @@
+// 2D Bondi-Hoyle-Lyttleton ultra-relativistic accretion problem onto a static (Schwarzschild) black hole, for the general relativistic Euler equations,
+// assuming a stiff equation of state.
+// Input parameters describe wind accretion of an ultra-relativistic gas onto a non-rotating black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_bhl_static_tetrad.c

@@ -1,3 +1,11 @@
+// 2D Bondi-Hoyle-Lyttleton ultra-relativistic accretion problem onto a static (Schwarzschild) black hole, for the general relativistic Euler equations in the tetrad basis,
+// assuming a stiff equation of state.
+// Input parameters describe wind accretion of an ultra-relativistic gas onto a non-rotating black hole.
+// Based on the analytical solution for stiff relativistic fluids presented in the article:
+// L. I. Petrich, S. L. Shapiro and S. A. Teukolsky (1988), "Accretion onto a moving black hole: An exact solution",
+// Physical Review Letters, Volume 60 (18): 1781-1784.
+// https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.1781
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_shock.c

@@ -1,3 +1,9 @@
+// Non-zero tangential velocity Riemann problem for the general relativistic Euler equations, assuming an ultra-relativistic equation of state.
+// Input parameters taken from the initial conditions in Figure 3 (Riemann problem 1), from the article:
+// P. Mach and M. Piętka (2010), "Exact solution of the hydrodynamical Riemann problem with nonzero tangential velocities and the ultrarelativistic equation of state",
+// Physical Review E, Volume 81 (4): 046313.
+// https://arxiv.org/abs/0905.0349
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_ultra_rel_shock_tetrad.c

@@ -1,3 +1,9 @@
+// Non-zero tangential velocity Riemann problem for the general relativistic Euler equations in the tetrad basis, assuming an ultra-relativistic equation of state.
+// Input parameters taken from the initial conditions in Figure 3 (Riemann problem 1), from the article:
+// P. Mach and M. Piętka (2010), "Exact solution of the hydrodynamical Riemann problem with nonzero tangential velocities and the ultrarelativistic equation of state",
+// Physical Review E, Volume 81 (4): 046313.
+// https://arxiv.org/abs/0905.0349
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_wald_magnetosphere_spinning.c

@@ -1,3 +1,10 @@
+// 2D Wald magnetosphere problem for a non-static (Kerr) black hole, for the general relativistic Maxwell equations.
+// Input parameters describe a uniform magnetic field surrounding rotating black hole.
+// Based on the analytical solution for force-free electrodynamics presented in the article:
+// R. M. Wald (1974), "Black hole in a uniform magnetic field",
+// Physical Review D, Volume 10 (6): 1680.
+// https://journals.aps.org/prd/abstract/10.1103/PhysRevD.10.1680
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_wald_magnetosphere_spinning_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Wald magnetosphere problem for a non-static (Kerr) black hole, for the general relativistic Maxwell equations in the tetrad basis.
+// Input parameters describe a uniform magnetic field surrounding rotating black hole.
+// Based on the analytical solution for force-free electrodynamics presented in the article:
+// R. M. Wald (1974), "Black hole in a uniform magnetic field",
+// Physical Review D, Volume 10 (6): 1680.
+// https://journals.aps.org/prd/abstract/10.1103/PhysRevD.10.1680
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_wald_magnetosphere_static.c

@@ -1,3 +1,10 @@
+// 2D Wald magnetosphere problem for a static (Schwarzschild) black hole, for the general relativistic Maxwell equations.
+// Input parameters describe a uniform magnetic field surrounding non-rotating black hole.
+// Based on the analytical solution for force-free electrodynamics presented in the article:
+// R. M. Wald (1974), "Black hole in a uniform magnetic field",
+// Physical Review D, Volume 10 (6): 1680.
+// https://journals.aps.org/prd/abstract/10.1103/PhysRevD.10.1680
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>

regression/rt_gr_wald_magnetosphere_static_tetrad.c

@@ -1,3 +1,10 @@
+// 2D Wald magnetosphere problem for a static (Schwarzschild) black hole, for the general relativistic Maxwell equations in the tetrad basis.
+// Input parameters describe a uniform magnetic field surrounding non-rotating black hole.
+// Based on the analytical solution for force-free electrodynamics presented in the article:
+// R. M. Wald (1974), "Black hole in a uniform magnetic field",
+// Physical Review D, Volume 10 (6): 1680.
+// https://journals.aps.org/prd/abstract/10.1103/PhysRevD.10.1680
+
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>