Using !-string and #-string commands

Using !-string and #-string commands#

!-strings are for setting simulation parameters#

!-strings are a convenient way of accessing multiple layers of a nested dictionary structure with a single string using the format:

"!<ALIAS>.<sub-dict>...<sub-dict>.<param>"

Any level of the nested dictionary can be reached by truncating the keyword.

Note: !-strings only work on UserCommands objects

Below is an example of how to use !-strings, using the example optical train.

import scopesim as sim
opt = sim.load_example_optical_train()

opt.cmds["!ATMO"]
[1] mapping
  • background:
    • filter_name: J
    • value: 16.6
    • unit: mag
  • element_name: basic_atmosphere
opt.cmds["!ATMO.background"]
[1] mapping
  • filter_name: J
  • value: 16.6
  • unit: mag
opt.cmds["!ATMO.background.filter_name"]

'J'

#-strings are for accessing Effect object parameters#

Similar to !-strings, #-strings allow us to get at the preset values inside the Effect-objects of the optical system. #-strings allow us to pring the contents of an effect’s meta dictionary.

Note: !-strings only work on OpticalTrain objects

Here, we’re again using the example optical train defined above. First let’s list the effects:

opt.effects
Table length=19
elementnameclassincluded
str16str22str29bool
basic_atmosphereatmospheric_radiometryAtmosphericTERCurveTrue
basic_telescopepsfSeeingPSFTrue
basic_telescopetelescope_reflectionTERCurveTrue
basic_instrumentstatic_surfacesSurfaceListTrue
basic_instrumentfilter_wheel : [J]FilterWheelTrue
basic_instrumentslit_wheel : [narrow]SlitWheelFalse
basic_instrumentimage_slicerApertureListFalse
basic_detectordetector_windowDetectorWindowTrue
basic_detectordetector_3dDetectorList3DFalse
basic_detectorqe_curveQuantumEfficiencyCurveTrue
basic_detectorexposure_integrationExposureIntegrationTrue
basic_detectordark_currentDarkCurrentTrue
basic_detectorshot_noiseShotNoiseTrue
basic_detectordetector_linearityLinearityCurveTrue
basic_detectorreadout_noisePoorMansHxRGReadoutNoiseTrue
basic_detectorsource_fits_keywordsSourceDescriptionFitsKeywordsTrue
basic_detectoreffects_fits_keywordsEffectsMetaKeywordsTrue
basic_detectorconfig_fits_keywordsSimulationConfigFitsKeywordsTrue
basic_detectorextra_fits_keywordsExtraFitsKeywordsTrue

We list the meta dictionary contents by using the string format

"#<effect-name>."

Note: The . at the end is important, otherwise the optical train will look for a non-existant effect named #<effect-name>

opt["#exposure_integration."]

{'filename': None,
 'description': 'Summing up sky signal for all DITs and NDITs',
 'history': [],
 'name': 'exposure_integration',
 'image_plane_id': 0,
 'temperature': -230,
 'dit': '!OBS.dit',
 'ndit': '!OBS.ndit',
 'width': 1024,
 'height': 1024,
 'x': 0,
 'y': 0,
 'element_name': 'basic_detector',
 'include': True,
 'cmds': CurrObs contents:

CurrSys contents:
├─OBS:
│ ├─instrument: basic_instrument
│ ├─psf_fwhm: 1.5
│ ├─modes: ['imaging']
│ ├─dit: 60
│ ├─ndit: 1
│ ├─slit_name: narrow
│ ├─wavelen: 2.1
│ ├─include_slit: False
│ ├─include_slicer: False
│ ├─include_det_window: True
│ ├─include_det_3d: False
│ └─filter_name: J
├─ATMO:
│ ├─background:
│ │ ├─filter_name: J
│ │ ├─value: 16.6
│ │ └─unit: mag
│ └─element_name: basic_atmosphere
├─TEL:
│ ├─telescope: Basic Telescope
│ ├─temperature: 0
│ ├─element_name: basic_telescope
│ ├─area: 0.19634954084936207 m2
│ └─etendue: 0.007853981633974483 arcsec2 m2
├─INST:
│ ├─temperature: -190
│ ├─pixel_scale: 0.2
│ ├─plate_scale: 20
│ └─element_name: basic_instrument
└─DET:
  ├─image_plane_id: 0
  ├─temperature: -230
  ├─dit: !OBS.dit
  ├─ndit: !OBS.ndit
  ├─width: 1024
  ├─height: 1024
  ├─x: 0
  ├─y: 0
  └─element_name: basic_detector

SystemDict contents:
├─SIM:
│ ├─spectral:
│ │ ├─wave_min: 0.3
│ │ ├─wave_mid: 2.2
│ │ ├─wave_max: 20
│ │ ├─wave_unit: um
│ │ ├─spectral_bin_width: 0.0001
│ │ ├─spectral_resolution: 5000
│ │ ├─minimum_throughput: 1e-06
│ │ └─minimum_pixel_flux: 1
│ ├─sub_pixel:
│ │ ├─flag: False
│ │ └─fraction: 1
│ ├─random:
│ │ └─seed: None
│ ├─computing:
│ │ ├─chunk_size: 2048
│ │ ├─max_segment_size: 16777217
│ │ ├─oversampling: 1
│ │ ├─spline_order: 1
│ │ ├─flux_accuracy: 0.001
│ │ ├─preload_field_of_views: False
│ │ └─nan_fill_value: 0.0
│ ├─file:
│ │ ├─example_data:
│ │ │ ├─suburl: example_data
│ │ │ └─hash_file: example_data_registry.txt
│ │ ├─psfs:
│ │ │ ├─suburl: psfs
│ │ │ └─hash_file: psfs_registry.txt
│ │ ├─atmo:
│ │ │ ├─suburl: atmo
│ │ │ └─hash_file: atmo_registry.txt
│ │ ├─local_packages_path: /home/docs/checkouts/readthedocs.org/user_builds/scopesim/checkouts/docs-effects-documentation/scopesim/tests/mocks
│ │ ├─server_base_url: https://scopesim.univie.ac.at/InstPkgSvr/
│ │ ├─retries: 3
│ │ ├─use_cached_downloads: False
│ │ ├─search_path: ['./inst_pkgs/', './']
│ │ └─error_on_missing_file: False
│ ├─reports:
│ │ ├─ip_tracking: False
│ │ ├─verbose: False
│ │ ├─rst_path: ./reports/rst/
│ │ ├─latex_path: ./reports/latex/
│ │ ├─image_path: ./reports/images/
│ │ ├─image_format: png
│ │ └─preamble_file: None
│ └─tests:
│   ├─run_integration_tests: True
│   └─run_skycalc_ter_tests: True
├─OBS:
├─TEL:
│ ├─etendue: 0
│ └─area: 0
└─INST:
  ├─pixel_scale: 0
  ├─plate_scale: 0
  └─decouple_detector_from_sky_headers: False}

We print a specific meta parameter by adding it after the .

opt["#exposure_integration.ndit"]

'!OBS.ndit'

Notice that the value of this dictionary entry is itself a !-string. We can resolve this by adding a ! to the end of the string, to force it to get the actual value from opt.cmds:

opt["#exposure_integration.ndit!"]

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