Using !-string and #-string commands

!-strings are for setting simulation parameters

TL;DR

import scopesim as sim
opt = sim.load_example_optical_train()
opt.cmds["!ATMO"]
opt.cmds["!ATMO.background"]
opt.cmds["!ATMO.background.filter_name"]

!-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.

import scopesim as sim
opt = sim.load_example_optical_train()

opt.cmds["!ATMO"]

{'background': {'filter_name': 'J', 'value': 16.6, 'unit': 'mag'},
 'element_name': 'basic_atmosphere'}

opt.cmds["!ATMO.background"]

{'filter_name': 'J', 'value': 16.6, 'unit': 'mag'}

opt.cmds["!ATMO.background.filter_name"]

'J'

#-strings are for accessing Effect object parameters

TL;DR

opt.effects
opt["#exposure_action."]
opt["#exposure_action.ndit"]
opt["#exposure_action.ndit!"]

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.

First let’s list the effects

opt.effects

Table length=17

element	name	class	included
str16	str22	str29	bool
basic_atmosphere	atmospheric_radiometry	AtmosphericTERCurve	False
basic_telescope	psf	SeeingPSF	True
basic_telescope	telescope_reflection	TERCurve	True
basic_instrument	static_surfaces	SurfaceList	True
basic_instrument	filter_wheel : [J]	FilterWheel	True
basic_instrument	slit_wheel : [narrow]	SlitWheel	False
basic_detector	detector_window	DetectorWindow	True
basic_detector	qe_curve	QuantumEfficiencyCurve	True
basic_detector	exposure_action	SummedExposure	True
basic_detector	dark_current	DarkCurrent	True
basic_detector	shot_noise	ShotNoise	True
basic_detector	detector_linearity	LinearityCurve	True
basic_detector	readout_noise	PoorMansHxRGReadoutNoise	True
basic_detector	source_fits_keywords	SourceDescriptionFitsKeywords	True
basic_detector	effects_fits_keywords	EffectsMetaKeywords	True
basic_detector	config_fits_keywords	SimulationConfigFitsKeywords	True
basic_detector	extra_fits_keywords	ExtraFitsKeywords	True

We list the meta dictionary contents by using the string format

"#<effect-name>."

opt["#exposure_action."]

{'filename': None,
 'description': 'Summing up sky signal for all DITs and NDITs',
 'history': [],
 'name': 'exposure_action',
 'image_plane_id': 0,
 'temperature': -230,
 'dit': '!OBS.dit',
 'ndit': '!OBS.ndit',
 'width': 1024,
 'height': 1024,
 'x': 0,
 'y': 0,
 'element_name': 'basic_detector',
 'z_order': [860],
 'include': True}

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

opt["#exposure_action.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_action.ndit!"]

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