Transition is a class which represents a transformation from one Instrument to another.

Each Transition has a TransitionType, a string indicating what was done to create the Instrument. If it exists, the Transition also references the previous Instrument object that was an input to whatever transformation was applied, aswell as a JSON encodable dictionary of metadata to represent parameters that may be useful when analyzing instrument history. Additionally, the Transition can reference a WrightTools Data object that was used as an input to the transformation, if it exists. The data object is placed into the attune store when stored, but not included in the JSON serialization.

create transition

create is the default transition for a new Instrument which is not based on a previous Instrument.

This is what is applied when you create an instrument using the Python constructor (Instrument).

map transitions

map transitions come in two flavors: attune.map_ind_points() and attune.map_ind_limits(). map transitions involve interpolating tunes onto new independent values using the outputs of the existing tunes.

attune.map_ind_points() is given an array of new independent values to use as independent values for a particular tune in a particular arrangement.

out = attune.map_ind_points(instr, "arr", "tune", [400, 600, 800], units="nm")

attune.map_ind_limits() is similar, but instead only cares about setting the bounding limits of the tune. Here, the number of points in the tune is preserved, but remapped onto a linear space from min to max.

out = attune.map_ind_limits(instr, "arr", "tune", 12500, 25000, units="wn")

Each of these optionally allow specifying units, and in the case of attune.map_ind_limits() the points will be linearly spaced in the units provided, but converted to the native units of the instrument for interpolation.

offset transitions

Like map transitions, offset transitions come in two flavors: attune.offset_by() and attune.offset_to(). offset transitions apply a static scalar offset to all dependent values in a tune.

For attune.offset_by(), you provide the relative value of the change which is directly added to the dependent values of the specified tune.

# Add pi to the output values of the "tune" tune in the "arr" arrangement
out = attune.offset_by(instr, "arr", "tune", 3.14)

For attune.offset_to(), you instead provide the absolute dependent value of the tune at a specific indepedent value of the specified tune.

# Offset by the scalar value which makes instr(532, "arr")["tune"] == 2.71
out = attune.offset_to(instr, "arr", "tune", 2.71, 532)

restore transition

restore is the transition which is created when you use attune.restore() to bring an old instrument object back to the head of the Attune Store.

See The Attune Store for more information.

rename transition

rename is the transition created by attune.rename(). Since the name is the key for the Attune Store, this transition breaks the history tracking, though the old name is provided for reference in the metadata.

out = attune.rename(instr, "out")

update_merge transition

update_merge is the transition created by attune.update_merge(). This transition allows the merging of two instrument objects into a single instrument object. This is useful for operations such as Spectral Delay Correction, where an instrument is generated indpendent of a previous instrument, but must be integrated to logically group arrangements together.

out = attune.update_merge(instr1, instr2)

If the input instruments do not share any arrangements, then this operation is equivalent to simply creating a new instrument with all of the arrangements of both inputs. If the input instruments do share arrangements, then instr2 will take precedence on a tune by tune basis.

instr1 is considered the previous instrument and is used to determine the name field of the output instrument.

tuning transitions

There are four tuning methods which incorporate measured data to generate or update Instrument objects: attune.tune_test(), attune.intensity(), attune.setpoint(), and attune.holistic(). More information can be found at Tuning Transitions.