step_current_generator – Provide a piecewise constant DC input current
======================================================================

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

The ``dc_generator`` provides a piecewise constant DC input to the
connected node(s).  The amplitude of the current is changed at the
specified times. The unit of the current is pA.

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

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 current changes
which typically would not fall onto simulation time steps.

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

amplitude_times
    Times at which current changes (list of times in ms)

amplitude_values
    Amplitudes of step current current (list of currents in pA)

allow_offgrid_times
    Boolean indicating if offgrid times should be used (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
+++++

CurrentEvent

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