/*
* test_iaf.sli
*
* This file is part of NEST.
*
* Copyright (C) 2004 The NEST Initiative
*
* NEST is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* NEST is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with NEST. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* BeginDocumentation
Name: testsuite::test_iaf - sli script for overall test of iaf_neuron model
Synopsis: (test_iaf) run -> compares response to current step with reference data
Description:
test_iaf.sli is an overall test of the iaf_neuron model connected
to some useful devices.
A DC current is injected into the neuron using a current generator
device. The membrane potential as well as the spiking activity are
recorded by corresponding devices.
It can be observed how the current charges the membrane, a spike
is emitted, the neuron becomes absolute refractory, and finally
starts to recover.
The timing of the various events on the simulation grid is of
particular interest and crucial for the consistency of the
simulation scheme.
Although 0.1 cannot be represented in the IEEE double data type, it
is safe to simulate with a resolution (computation step size) of 0.1
ms because by default nest is built with a timebase enabling exact
representation of 0.1 ms.
The expected output is documented and briefly commented at the end of
the script. The textual output of the voltmeter documented in this file
can be regenerated by setting adding /to_screen true to the SetStatus
call of vm below.
Other test programs discuss the various aspects of this script in detail,
see the SeeAlso key below.
Author: July 2004, Diesmann
SeeAlso: iaf_neuron, testsuite::test_iaf_i0, testsuite::test_iaf_i0_refractory, testsuite::test_iaf_dc
*/
/unittest (6666) require
/unittest using
0.1 /h Set
ResetKernel
0 <<
/local_num_threads 1
/resolution h
>> SetStatus
/iaf_neuron Create /neuron Set
/dc_generator Create /dc_gen Set
dc_gen << /amplitude 1000. >> SetStatus
/voltmeter Create /vm Set
vm << /withtime true /time_in_steps true /interval h >> SetStatus
/spike_detector Create /sp_det Set
sp_det << /withtime true /withgid true /time_in_steps true >> SetStatus
dc_gen neuron 1.0 h Connect
vm neuron 1.0 h Connect
neuron sp_det 1.0 h Connect
8 Simulate
{ % reference data
dup Transpose First /test_times Set % times of reference
vm [/events [/times /V_m]] get cva % array of recorded data
6 ToUnitTestPrecision % to precision of reference
Transpose % all recorded tuples
{First test_times exch MemberQ } Select % those with reference
eq % compare
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Expected output of this program:
%
% The output send to std::cout is a superposition of the output of
% the voltmeter and the spike detector. Both, voltmeter and spike
% detector are connected to the same neuron.
%
% time (in steps) voltage (in mV)
[
[ 1 -70 ] %<----- The earliest time dc_gen can be switched on.
[ 2 -70 ] %<----- The DC current arrives at the neuron, it is
[ 3 -69.602 ] %<- reflected in the neuron's state variable y0,
[ 4 -69.2079 ] % | (initial condition) but has not yet affected
[ 5 -68.8178 ] % | the membrane potential.
[ 6 -68.4316 ] % |
[ 7 -68.0492 ] % --- the effect of the DC current is visible in the
[ 8 -67.6706 ] % membrane potential
[ 9 -67.2958 ] %
[ 10 -66.9247 ] %
%
% ...
%
[ 45 -56.0204 ] %
[ 46 -55.7615 ] %
[ 47 -55.5051 ] %
[ 48 -55.2513 ] %
[ 49 -55.0001 ] %
[ 50 -70 ] % <---- The membrane potential crossed threshold in the
[ 51 -70 ] % step 4.9 ms -> 5.0 ms. The membrane potential is
[ 52 -70 ] % reset (no super-threshold values can be observed).
[ 53 -70 ] % The spike is reported at 5.0 ms
[ 54 -70 ] %
[ 55 -70 ] %
[ 56 -70 ] %
[ 57 -70 ] %
[ 58 -70 ] %
[ 59 -70 ] %
[ 60 -70 ] %
[ 61 -70 ] %
[ 62 -70 ] %
[ 63 -70 ] %
[ 64 -70 ] %
[ 65 -70 ] %
[ 66 -70 ] %
[ 67 -70 ] %
[ 68 -70 ] %
[ 69 -70 ] %
[ 70 -70 ] % <---- The last point in time at which the membrane potential
[ 71 -69.602 ] % <- is clamped. The fact that the neuron is not refractory
[ 72 -69.2079 ] % | anymore is reflected in the state variable r==0.
[ 73 -68.8178 ] % | The neuron was refractory for 2.0 ms.
[ 74 -68.4316 ] % |
[ 75 -68.0492 ] % --- The membrane potential starts to increase
[ 76 -67.6706 ] % immediately afterwards and the neuron can generate
[ 77 -67.2958 ] % spikes again (at this resolution reported with time
[ 78 -66.9247 ] % stamp 7.1 ms on the grid)
[ 79 -66.5572 ] % <--
] % |
% |
% - The simulation was run for 8.0 ms. However, in the step
% 7.9 ms -> 8.0 ms the voltmeter necessarily receives the
% voltages that occurred at time 7.9 ms (delay h). This
% results in different end times of the recorded voltage
% traces at different resolutions. In the current
% simulation kernel there is no general cure for this
% problem. One workaround is to end the simulation script
% with "h Simulate", thereby making the script resolution
% dependent.
%
exch assert_or_die