Usage

Configuration file

First you need to create a configuration file, see example_config.cfg included in the package or in the repository.

It first defines some global configuration options like output \(N_{side}\), the unit and the channels, then has 2 subsections. They both define subsections with a class attribute that specifies which object should be instantiated; all other arguments are passed into the class constructor.

• The pysm_components subsection allows to choose any pre-existing PySM model and later add any custom class, for example one from so_pysm_models.

• The other_components section instead includes models that generate a map to be summed after PySM has been executed, for example the noise simulation.

mapsims_run

mapsims_run is a script included in the package, it can be used to execute pipelines described in a configuration file in the terminal:

mapsims_run example_config.cfg

MapSims object

Create the simulator object with:

import mapsims
simulator = mapsims.from_config("example_config.cfg")

This returns a MapSims object, then you can produce the output map with:

output_map = simulator.execute()

Python classes

Using instead the Python classes, we first need to create the custom component objects, as an example we will use all defaults options:

NSIDE = 16
dust = so_pysm_models.GaussianDust(
    target_nside=NSIDE,
)

sync = so_pysm_models.GaussianSynchrotron(
    target_nside=NSIDE,
)

Then we can create a SONoiseSimulator, the most important parameter is the scanning strategy, it can be either “classical” or “opportunistic”:

noise = mapsims.SONoiseSimulator(
    telescope="SA",
    band=27,
    nside=NSIDE,
    return_uK_CMB=True,
    sensitivity_mode="baseline",
    apply_beam_correction=True,
    apply_kludge_correction=True,
    scanning_strategy="classical",
    LA_number_LF=1,
    LA_number_MF=4,
    LA_number_UHF=2,
    SA_years_LF=1,
    SA_one_over_f_mode="pessimistic",
    SA_remove_kluge=False,
)

Finally we can create the MapSim simulator object and pass the PySM custom component and the noise simulator as dictionaries, we can also specify any default model from PySM as a comma separated string, e.g. “d7,a1,s2”:

simulator = mapsims.MapSim(
    telescope="SA",
    band=27,
    nside=NSIDE,
    unit="uK_CMB",
    pysm_components_string="a1",
    pysm_custom_components={"dust": dust, "synchrotron": sync},
    other_components={"noise": noise},
)

and compute the output map using the execute method:

output_map = simulator.execute()