Name: testsuite::test_iaf_dc - li script for test of iaf_psc_alpha with external DC current

Synopsis:

(test_iaf_dc) run -&gt; compare cout with comments in file


Description:

test_iaf_dc.sli is a test of a specific feature of the iaf_psc_alpha 
model. It is tested at which time and how an external DC current affects 
the state of the neuron, the membrane potential in particular. 
This is probably the simplest setup demonstrating how an external 
continuous function (the DC) can be incorporated into a system with 
point event interaction. A general introduction, including examples 
not restricted to piecewise constant functions, can be found in [1]. 
The expected output is documented and briefly commented at the end of 
the script. 
Cleary, the result of this script is not resolution independent. The 
choice of the computation step size determines at which point in time 
the current affects the neuron. 
There are 2 problems with this script: 
1. A network element (here the DC generator) can only change its state 
when it performs a computation (update) step t -&gt; t + h. 
Thus, the earliest possible time the DC generator can be switched on 
is at t=h. This is the default. Therefore, the time of onset depends 
on the computation step size. 
2. The default delay between the DC generator and the neuron is the minimal 
allowed value of 1 h. Therefore, the delay of the current depends on 
the computation step size. 
A sequence of further test scripts (SeeAlso key below) demonstrates and 
verifies how the SLI script can be made independent of the computation 
step size. This leads to properly aligned and identical voltage traces 
for simulations carried out with different computation step sizes.


References:

[1] Rotter S &amp; Diesmann M (1999) Exact simulation of time-invariant linear 
systems with applications to neuronal modeling. Biologial Cybernetics 
81:381-402.


Author:

February 2004, Diesmann, Gewaltig, Plesser


SeeAlso:

iaf_psc_alpha
testsuite::test_iaf_dc_aligned
testsuite::test_iaf_dc_aligned_delay
testsuite::test_iaf_dc_aligned_stop

Source:

/var/www/debian/nest/nest-simulator-2.20.0/testsuite/unittests/test_iaf_dc.sli
