Phantom config

Phantom config files: parse, convert, modify, and generate.

phantomconfig can read Phantom .in and .setup files. (They have the same format.) You can, for example:

• modify config values,
• add new variables,
• write the config as a JSON file,
• generate a config file from a dictionary.

Usage

Basic usage

Import phantomconfig as pc.

>>> import phantomconfig as pc

To read in a Phantom config file

>>> input_file = pc.read_config('prefix.in')

Print a summary

>>> input_file.summary()

The variables, with their values, comment string, and the block they are a member of, are stored in a dictionary accessed by the .config method.

>>> dtmax = input_file.config['dtmax']

The keys of this dictionary correspond to the variable name, and values are a ConfigVariable named tuple with the variable name, value, comment, and block.

>>> dtmax.name
>>> dtmax.value
>>> dtmax.comment
>>> dtmax.block

If you like, you can write the Phantom config as a JSON file, and you can read the JSON file.

>>> input_file.write_json('prefix-in.json')
>>> json_file = pc.read_json('prefix-in.json')

Check that the configs are equal

>>> input_file.config == json_file.config

You can add a new variable, remove a variable, and change the value of a variable.

# Add new variable
>>> input_file.add_variable(
... 'new_var',
... 12345678,
... comment='Sets thing',
... block='options controlling things',
... )

# Remove a variable
>>> input_file.remove_variable('dtmax')

# Change the value of a variable
>>> input_file.change_value('dumpfile', 'new_dumpfile_name')

Examples

Generate a config from a dictionary

You can create a Phantom .setup file from a Python dictionary. First create the dictionary

>>> setup = {
... 'cs': [cs, 'sound speed', 'gas properties'],
... 'npart': [npart, 'number of particles in x direction', 'gas properties'],
... 'rhozero': [rhozero, 'initial density', 'gas properties'],
... 'ilattice': [ilattice, 'lattice type', 'gas properties'],
... }

Then you can read the dictionary with phantomconfig, and write to a Phantom .setup file

>>> setup_config = pc.read_dict(setup)
>>> setup_config.header = ['input file for some particular setup routine']
>>> setup_config.write_phantom('filename.setup')

This writes a file like

# input file for some particular setup routine

# gas properties
                  cs =        1.000   ! sound speed
               npart =         9999   ! number of particles in x direction
             rhozero =        0.100   ! initial density
            ilattice =            2   ! lattice type

Writing multiple configs

Say you want to write multiple configs, each with a different parameter value. For example, you have a template .in file and you want to vary the alpha parameter. The following

1. reads the template file
2. loops over a list of alpha values, writing a new .in file for each value in the list

alphas = [0.1, 0.2, 0.3]
infile = pc.read_config('template.in')

for alpha in alphas:
    infile.change_value('alpha', alpha)
    infile.write_phantom(f'alpha={alpha}.in')