Performing multiple measurements
=================================
Sometimes it may be desired to perform multiple measurements at each scan point.

Multiple measurements without models
------------------------------------
When models are not being used,
the scan framework is instructed to perform multiple measurements by setting the :code:`measurements`
attribute of the scan to a list of strings containing the name of each measurement, as in the following example.

.. code-block:: python

    def build(self, **kwargs):
        # define two separate measurements
        self.measurements = ['rsb', 'bsb']

    @kernel
    def measure(self, time):
        self.cooling.doppler()

        # perform a blue side-band measurement
        if self.measurement == 'bsb':
            self.raman.set_frequency(self.raman.m1_bsb_frequency)
            self.raman.pulse(self.raman_readout_time)

        # perform a red side-band measurement
        if self.measurement == 'rsb':
            self.raman.set_frequency(self.raman.m1_rsb_frequency)
            self.raman.pulse(self.raman_readout_time)

        # rsb or bsb counts
        counts = self.detection.detect()
        return counts

When :code:`self.measurements` is set, the framework sets :code:`self.measurement` to the name of the current
measurement prior to calling :code:`measure()` and :code:`measure()` is called separately
for each defined measurement.  In the example above, the measure method is called :code:`2 * nrepeats` times at
each scan point: :code:`nrepeats` times for each measurement.  Measurements are executed in the order that
they appear in :code:`self.measurements` and are interleaved such that each successive call to
:code:`measure` will have :code:`self.measurement` set to the name of a different measurement.

Multiple measurements when using models
---------------------------------------
When using models, measurements are defined by simply setting the :code:`measurement` attribute of
:meth:`register_model <scan_framework.scans.scan.Scan.register_model>`

.. code-block:: python

    def register_models(self):
        # create models to store data for each measurement
        self.bsb_model = BsbModel(self)
        self.rsb_model = RsbModel(self)

        # register each model with it's associated measurement
        self.register_model(self.bsb_model, measurement='bsb')
        self.register_model(self.rsb_model, measurement='rsb')

The framework will automatically append the measurement name to :code:`self.measurements` and all
data generated by that measurement will be processed and saved by the scan model instance that is
registered for the nammed measurement.