Configuration Reference

Thor uses YAML configuration files. This page documents all available options.

File Structure

# Global settings
## Required
dataset_type: 'shellmodel'
driver_type: 'mcrtsimulation'

## Optional
device: "cpu"          # options: "cpu" or "gpu"
log_level: info        # options: trace, debug, info, warn, error
log_dir: "./logs"

# Dataset section (name must match dataset_type)
shellmodel:
  # ...

Global Settings

Parameter	Type	Default	Description
`dataset_type`	string	required	Dataset geometry type
`driver_type`	string	required	Simulation driver
`device`	string	`"cpu"`	Compute device
`log_level`	string	`"debug"`	Logging verbosity
`log_dir`	string	`"./logs"`	Log output directory

Dataset Types

shellmodel - Spherical shell
powerlaw_shellmodel - Power-law shell profiles
unigrid - Uniform Cartesian grid
infiniteslab - Infinite slab
pointcloud_voronoi - Voronoi tessellation (experimental)
pointcloud_voronoi_tree - Tree-accelerated Voronoi (incomplete)
pointcloud_sph - SPH interpolation (incomplete)

Driver Types

mcrtsimulation - Monte Carlo Radiative Transfer
raytracer - Forward ray tracing (projections, absorption spectra, tracers, etc)

MCRT Simulation Settings

mcrtsimulation:
  outputpath: output
  overwrite: true
  linename: Lya

  # Photon control
  nphotons_max: 100000
  nphotons_step_max: 100000
  nsteps_per_photon_max: 10000000

  # Physics
  xcrit: 3.0
  acc_scheme: Smith15
  interactor: ResonantWithDustInteractor

  # Stepping
  max_step: 1.0
  min_step: 0.0

  # Boundary conditions
  pbc: false
  allow_outofbox: false

  # Emission model
  emissionmodel:
    # ...

  # Output processors
  outputprocessors:
    # ...

MCRT Parameters

Parameter	Type	Default	Description
`outputpath`	string	`"output"`	Output directory
`overwrite`	bool	`false`	Overwrite existing output
`linename`	string	`"Lya"`	Emission line name
`nphotons_max`	int	-	Max photons in memory
`nphotons_step_max`	int	-	Max photons spawned per step
`nsteps_per_photon_max`	int	-	Max steps per photon
`xcrit`	float	`0.0`	Forced critical frequency for line wings
`acc_scheme`	string	`"Smith15"`	Acceleration scheme
`interactor`	string	-	Interaction model
`max_step`	float	-	Maximum step length
`pbc`	bool	`false`	Periodic boundary conditions
`use_peeling`	bool	`false`	Enable peeling photons

Acceleration Schemes

Only use values other than none with Lyman-alpha.

Value	Description
`none`	No acceleration
`Smith15`	Smith et al. 2015
`Laursen09`	Laursen et al. 2009

Interactors

Value	Description
`SimpleInteractor`	Basic resonant scattering
`ResonantWithDustInteractor`	Includes dust absorption
`ResonantDoubletInteractor`	Doublet lines (e.g., MgII)

Emission Models

Single Source

emissionmodel:
  mode: "singlesource"
  singlesource:
    nphotons: 1000
    lum_total: 1e42
    position: [0.5, 0.5, 0.5]
    forced_weight: 1.0  # optional

List Source

emissionmodel:
  mode: "listsource"
  listsource:
    loader: gadget
    nphotons_per_source_min: 1
    nphotons_per_source_max: 1000

Dataset Source

emissionmodel:
  mode: "datasetsource"
  datasetsource:
    # Uses emission field from dataset loader

Output Processors

We allow for different raw and processed outputs. The most commonly used output format for now is the raw Monte Carlo photon output.

outputprocessors:
  - type: "photon"
    active: true

  - type: "histogram1d"
    field: "dlambda"
    weight: "weight"
    left: -1.5
    right: 1.5
    nbins: 30
    assess_convergence: true
    convergence_threshold: 0.1

Photon Output

Writes escaped photon data to HDF5.

Parameter	Type	Description
`active`	bool	Enable this processor

Histogram 1D

Experimental

This feature is experimental and may change.

Bins photon field values into a histogram (e.g., spectrum).

Parameter	Type	Description
`field`	string	Field to histogram (e.g., `"dlambda"`)
`weight`	string	Weight field (e.g., `"weight"`)
`left`	float	Left bin edge
`right`	float	Right bin edge
`nbins`	int	Number of bins
`assess_convergence`	bool	Check convergence
`convergence_threshold`	float	Convergence tolerance

Dataset-Specific Configuration

See Datasets for detailed configuration of each dataset type.