/*
* test_iaf_ps_psp_poisson_accuracy.sli
*
* This file is part of NEST.
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* 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
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* 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/>.
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*/
/* BeginDocumentation
Name: testsuite::test_iaf_ps_psp_poisson_accuracy - probes interaction of precise poisson generator and neuron model
Synopsis: (test_iaf_ps_psp_poisson_accuracy) run -> compare with analytical result
Description:
The test probes the interaction of a spike generator implementing a
poisson process in continuous time with a neuron model capable of
handling off-grid spike times. The result is verified by comparing the
superposition of post-synaptic potentials in the neuron model to the
the corresonding analytical solution. To achieve this, spike
generation of the neuron mode is prevented by setting the spike
threshold to a very high value. The test employs the parrot neuron for
precise spike times to provide the neuron model and the spike detector
with an identical sequence of spike times. The independence of the
result from the computations step size is ensured by comparing the
results for a range of temporal resolutions. Due to this setup the
test requires that several critical timing relations between network
nodes of different types operate correctly. If the test fails go back
to simpler tests verifying individual node types.
Author: May 2005, February 2008, March 2009; Diesmann
References:
[1] Morrison A, Straube S, Plesser H E, & Diesmann M (2007) Exact Subthreshold
Integration with Continuous Spike Times in Discrete Time Neural Network
Simulations. Neural Computation 19:47--79
SeeAlso: testsuite::test_iaf_ps_psp_accuracy, testsuite::test_iaf_ps_dc_accuracy
*/
/unittest (6335) require
/unittest using
M_ERROR setverbosity
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Parameters of simulation schedule.
%
-10 /min_exponent Set
1.0 /delay Set % in ms
65.0 /weight Set % in pA
[-4 min_exponent -2] Range /hlist Set
1e-13 /tolerance Set % in mV
%100.0 /T Set
5.0 /T Set
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Parameters of neuron model.
%
<<
/E_L 0.0 % resting potential in mV
/V_m 0.0 % initial membrane potential in mV
/V_reset 0.0
/V_th 1000.0 % spike threshold in mV
/I_e -530.0 % DC current in pA
/tau_m 10.0 % membrane time constant in ms
/tau_syn 0.3 % PSC rise time in ms
/C_m 250.0 % membrane capacity in pF
>> /params Set
/rate 16.0 def % in spikes/ms
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Reference value
%
% The function /potential computes the exact value of the membrane
% potential at the end of the simulation for a given input spike train.
%
/psp
[/t]
(
UnitStep(t)*weight * E/tau_syn * 1/C_m
* ( (exp(-t/tau_m)-exp(-t/tau_syn))/(1/tau_syn - 1/tau_m)^2 - t*exp(-t/tau_syn)/(1/tau_syn - 1/tau_m) )
)
Function
def
/dc
[/t]
( I_e*tau_m/C_m*(1-exp(-t/tau_m)) )
Function
def
/potential
{ % argument is the input spike train
params begin
( psp(T-t-delay) ) /t Function Map
Sort Total % the present Total does not control accuracy
T dc add
end
} def
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Simulation for a given computation step size
%
/AlignedImpact
[/i /model]
{
i dexp /h Set % computation step size in ms
ResetKernel
0 << /tics_per_ms min_exponent neg dexp /resolution h >> SetStatus
/poisson_generator_ps Create /pg Set
pg << /rate rate 1000.0 mul >> SetStatus % rate in Hz
/parrot_neuron_ps Create /pn Set
model Create /n Set
n params SetStatus
/spike_detector Create /sd Set
sd << /precise_times true >> SetStatus
pg pn Connect
pn sd Connect
pn n weight delay Connect
T Simulate
sd [/events /times] get cva potential /V Set % potential from closed form expression
n /V_m get /Y Set % potential from simulation
[i Y Y V sub abs] % full results to enable detailed report
}
Function
def
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Perform simulations at all resolutions and collect results
%
{
hlist
{
/iaf_psc_alpha_canon AlignedImpact
}
Map
%dup print_details % uncomment for debugging
Transpose dup
[2] Part dup Rest exch First sub % check whether simulation results are
{tolerance lt} Map % identical for all resolutions
true exch {and} Fold
exch
[3] Part % check whether individual simulation results
{tolerance lt} Map % are identical to analytical solution
true exch {and} Fold
and
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% helper function for debugging,
% prints detailed table of results
%
/print_details
{
cout default 15 setprecision
endl endl endl
( h in ms ) <-
( simul. potential [mV]) <-
( error [mV]) <-
endl
(--------------------------) <-
(--------------------------) <-
(--------------------------) <-
endl
exch
{
{
exch 24 setw exch <- ( ) <-
}
forall
endl
}
forall
;
}
def
% executes the overall test
assert_or_die
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% RPN expression for the reference value
%
% Below is the code used to compute the reference value before
% the compiler for infix mathematical notation became available.
%
% V is the exact value of the membrane potential at the end
% of the simulation.
%
%params begin
%userdict begin
% << >> begin
%
% s
% {
% T exch sub delay sub /t Set
%
% t 0.0 geq
% {
% TauSyn inv Tau inv sub /dti Set
% weight C inv mul
% E TauSyn div mul
% t neg Tau div exp t neg TauSyn div exp sub
% dti dup mul div
% t t neg TauSyn div exp mul
% dti div
% sub mul
% }
% { 0.0 }
% ifelse
% } Map
%
% Sort
% 0 exch {add} forall
%
% % I0 Tau/C (1 -e^-T/Tau)
%
% I0 Tau C div mul 1.0 T neg Tau div exp sub mul
% add
%
% end
%end
%end
%
%/V Set
% garbage to be removed
% ---------------------
%
% [5 3 6 9] /a Set
% [-1 8 10 2] /b Set
%
%
% %/parrot_neuron Create /pn Set
%
%
%/mean_interval rate inv def % in ms
%rngdict /knuthlfg get 200 CreateRNG /rng Set
%rng rdevdict /poisson get CreateRDV /poiss Set
%poiss << /lambda rate T mul >> SetStatus
%poiss 1 RandomArray /n Set
% method 1: draw n random numbers uniformly distributed
% over the interval (0,T].
%
%n { pop rng drand 1.0 exch sub T mul} Table Sort /s Set
% method 2: draw n intervals from an exponential
% distribution. The parameter of the distribution
% is the mean interval of the Poisson process
%rng rdevdict /exponential get CreateRDV /expdist Set
%expdist n [1] Part RandomArray /s Set
%s {mean_interval mul } Map /s Set
%0.0 s {add} FoldList Rest /s Set