Runtime Parameters

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.

Parameters: