XRTM Option/solver table:

Option vs Solver doub_add eig_add eig_bvp four_stream mem_bvp pade_add single six_stream sos two_os two_stream
forward_derivs yes yes yes no yes yes yes no yes yes yes
reverse_derivs no yes yes no no no no no no no yes
delta_m yes yes yes yes yes yes yes yes yes yes yes
n_t_tms yes yes yes yes yes yes yes yes yes yes yes
four_conv_old yes yes yes yes yes yes n/a yes yes yes yes
four_conv_new yes yes yes yes yes yes n/a yes yes yes yes
no_azimuthal yes yes yes yes yes yes n/a yes yes yes yes
output_at_levels no no yes yes yes no yes yes no no yes
output_at_taus no no yes yes yes no yes yes no no yes
part_sol_classical yes yes yes yes no yes n/a yes n/a n/a yes
part_sol_greens yes yes yes no no yes n/a no n/a n/a no
phase_scalar yes yes yes yes yes yes yes yes yes yes yes
phase_matrix_gc yes yes yes no yes yes yes no yes yes no
phase_matrix_lc yes yes yes no yes yes yes no yes yes no
psa yes yes yes no yes yes yes no yes yes no
quad_norm_gaus_leg yes yes yes yes yes yes yes yes yes yes yes
quad_doub_gaus_leg yes yes yes yes yes yes yes yes yes yes yes
quad_lobatto no no no no no no no no no no no
save_leg_polys yes yes yes n/a yes yes yes n/a yes yes n/a
save_phase_mats yes yes yes n/a yes yes no n/a yes yes n/a
save_local_r_t yes yes yes n/a yes yes no n/a yes yes n/a
save_layer_r_t_s yes yes n/a n/a n/a yes n/a n/a n/a n/a n/a
save_total_r_t_s yes yes n/a n/a n/a yes n/a n/a n/a n/a n/a
sfi no no yes yes no no no yes no no yes
source_solar yes yes yes yes yes yes yes yes yes yes yes
source_thermal yes yes yes no no yes n/a no no no no
stack_reuse_adding partial partial n/a n/a n/a partial n/a n/a n/a n/a n/a
top_down_adding partial partial n/a n/a n/a partial n/a n/a n/a n/a n/a
bottom_up_adding yes yes n/a n/a n/a yes n/a n/a n/a n/a n/a
upwelling_output yes yes yes yes yes yes yes yes yes yes yes
downwelling_output yes yes yes yes yes yes yes yes yes yes yes
vector (n_stokes > 1) yes yes yes no yes yes yes no yes yes no
n_solar_thetas > 1 yes yes yes yes yes yes yes yes yes yes yes
n_out_thetas = 0 yes yes yes yes yes yes yes yes yes yes yes
n_out_thetas > 0 yes yes yes yes yes yes yes yes yes yes yes

XRTM Output/solver table:

Output vs Solver doub_add eig_add eig_bvp four_stream mem_bvp pade_add single six_stream sos two_os two_stream
radiance yes yes yes yes yes yes yes yes yes yes yes
radiance_mean yes yes yes yes yes yes yes yes yes yes yes
flux yes yes yes yes yes yes yes yes yes yes yes
flux_divergence yes yes yes yes yes yes yes yes yes yes yes