step_rate_generator – Provide a piecewise constant input rate
=============================================================

Description
+++++++++++

The ``rate_generator`` provides a piecewise constant rate input to the
connected rate unit(s). Please note that this input is handled in the same
way as input from any other rate unit, that is, it is processed by the input
function of the receiving rate unit. The amplitude of the rate is changed
at the specified times. The unit of the rate is Hz.

If ``allow_offgrid_times`` is false, times will be rounded to the nearest
grid point if they are less than tic/2 from the grid point, otherwise
NEST reports an error. If true, times are rounded to the nearest grid
point if within tic/2 from the grid point, otherwise they are rounded
up to the *end* of the grid point.

Times of amplitude changes must be strictly increasing after conversion
to simulation time steps. The option ``allow_offgrid_times`` may be
useful, for example, if you are using randomized times for rate changes
which typically would not fall onto simulation time steps.

.. include:: ../models/stimulation_device.rst

amplitude_times
    Times at which current changes (list of ms)

amplitude_values
    Amplitudes of step current current (list of pA)

allow_offgrid_times
    Default false

Set parameters from a stimulation backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The parameters in this stimulation device can be updated with input
coming from a stimulation backend.

The data structure used for the update holds pairs of values in the form

 [ (amplitude_times, amplitude_values), (amplitude_times, amplitude_values), ... ].

Thus, the size of the data for the step_rate_generator needs to be even.

Sends
+++++

DelayedRateConnectionEvent

See also
++++++++
:doc:`Device <index_device>`, :doc:`Generator <index_generator>`, :doc:`Rate <index_rate>`