Chapter 2. Runtime Parameters

The Ramses parameter file is based on the Fortran namelist syntax. The Sod test parameter file is shown below, as it should appear if you edit it.

$ more tube1d.nml
This is the RAMSES parameter file for Sod''s shock tube test.

&RUN_PARAMS
hydro=.true.
nsubcycle=3*1,2
/

&AMR_PARAMS
levelmin=3
levelmax=10
ngridmax=2000
nexpand=1
boxlen=1.0
/

&BOUNDARY_PARAMS
nboundary=2
ibound_min=-1,+1
ibound_max=-1,+1
bound_type= 1, 1
/

&INIT_PARAMS
nregion=2
region_type(1)='square'
region_type(2)='square'
x_center=0.25,0.75
length_x=0.5,0.5
d_region=1.0,0.125
u_region=0.0,0.0
p_region=1.0,0.1
/

&OUTPUT_PARAMS
noutput=1
tout=0.245
/

&HYDRO_PARAMS
gamma=1.4
courant_factor=0.8
slope_type=2
riemann='hllc'
/

&REFINE_PARAMS
err_grad_d=0.05
err_grad_u=0.05
err_grad_p=0.05
interpol_var=0
interpol_type=2
/

This parameter file is organized in namelist blocks. Each block starts with &BLOCK_NAME and ends with the character "/". Within each block, you can specify parameter values using standard Fortran namelist syntax. There are currently 11 different parameter blocks implemented in RAMSES.

4 parameters blocks are mandatory and must always be present in the parameter file. These are &RUN_PARAMS, &AMR_PARAMS, &OUTPUT_PARAMS and &INIT_PARAMS. The 8 other blocks are optional. They must be present in the file only if they are relevant to the current run. These are
&BOUNDARY_PARAMS, &HYDRO_PARAMS, &PHYSICS_PARAMS, &POISSON_PARAMS, &REFINE_PARAMS,&CLUMPFIND_PARAMS, &SINK_PARAMS and &MOVIE_PARAMS.

The variables you can set or adjust in each namelist block are described in more details in the following sections.

1. Global parameters
2. AMR grid
3. Initial conditions
4. Output parameters
5. Boundary conditions
6. Hydrodynamics solver
7. Physical parameters
8. Poisson solver
9. Refinement strategy
10. PHEW Clump finder
11. Particle Unbinding parameters
12. Merger Tree parameters
13. Sink particles
14. Movies
15. Turbulence driving
16. Tracer particles