Parameters

Adirondax allows the user to configure the simulation via the following set of parameters:

{
  "physics": {
    "hydro": { 
      "default": false,
      "description": "switch on for hydrodynamics."
    },
    "magnetic": { 
      "default": false,
      "description": "switch on for magnetic field."
    },
    "gravity": { 
      "default": false,
      "description": "switch on for self-gravity."
    },
    "external_potential": { 
      "default": false,
      "description": "switch on for external gravitational potential."
    },
    "quantum": { 
      "default": false,
      "description": "switch on for Schrodinger field."
    }
  },
  "mesh": {
    "type": {
      "default": "eulerian",
      "description": "options: 'eulerian', 'lagrangian', 'ale'."
    },
    "geometry": {
      "default": "cartesian",
      "description": "options: 'cartesian', 'axisymmetric'."
    },
    "box_size": { 
      "default": [1.0, 1.0],
      "description": "domain box size: (x,y), (x,y,z), (r,z)."
    },
    "resolution": { 
      "default": [32, 32],
      "description": "resolution per each dimension."
    },
    "boundary_condition": {
      "default": ["periodic", "periodic"],
      "description": "options: 'periodic', 'reflective' (per dimension)."
    }
  },
  "time": {
    "span": { 
      "default": 0.0,
      "description": "simulation span time."
    },
    "num_timesteps": { 
      "default": -1,
      "description": "set to a positive value to fix the number of (equi-spaced) timesteps."
    }
  },
  "output": {
    "path": {
      "default": "./checkpoints",
      "description": "path to output directory."
    },
    "num_checkpoints": {
      "default": 100,
      "description": "number of checkpoints to save."
    },
    "save": {
      "default": false,
      "description": "switch on to save checkpoints."
    },
    "plot_dynamic_range": {
      "default": 100.0,
      "description": "dynamic range for plotting."
    }
  },
  "hydro": {
    "eos": { 
      "type": {
        "default": "ideal",
        "description": "options: ideal, isothermal, tabular."
      },
      "gamma": {
        "default": 1.66666667,
        "description": "adiabatic index for 'ideal' gas."
      },
      "sound_speed": {
        "default": 1.0,
        "description": "isothermal sound speed for 'isothermal' gas."
      },
      "table_path": {
        "default": "./eos_table.h5",
        "description": "path to tabular EOS data file for 'tabular' gas."
      }
    },
    "riemann_solver": {
      "default": "llf",
      "description": "options: 'llf', 'hlld'."
    },
    "cfl": {
      "default": 0.5,
      "description": "CFL number for hydrodynamics timestep."
    },
    "slope_limiting": {
      "default": false,
      "description": "switch on to use slope limiting."
    }
  },
  "quantum": {
    "m_eV": { 
      "default": 1.0e-22,
      "description": "axion mass in eV."
    }
  },
  "cosmology": {
    "omega_matter": {
      "default": 0.3,
      "description": "matter density parameter."
    },
    "omega_lambda": {
      "default": 0.7,
      "description": "dark energy density parameter."
    },
    "little_h": {
      "default": 0.7,
      "description": "Hubble parameter little h (H_0 = 100 h km/s/Mpc)."
    }
  },
  "version": {
    "default": "unknown",
    "description": "adirondax version used (auto detected)."
  }
}