iaf_psc_exp_ps.h

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/*
 *  iaf_psc_exp_ps.h
 *
 *  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,
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 *  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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 */
 
#ifndef IAF_PSC_EXP_PS_H
#define IAF_PSC_EXP_PS_H
 
// C++ includes:
#include <vector>
 
// Generated includes:
#include "config.h"
 
// Includes from libnestutil:
#include "archiving_node.h"
#include "connection.h"
#include "event.h"
#include "iaf_propagator.h"
#include "nest_types.h"
#include "recordables_map.h"
#include "ring_buffer.h"
#include "slice_ring_buffer.h"
#include "universal_data_logger.h"
 
namespace nest
{
 
/* BeginUserDocs: neuron, integrate-and-fire, current-based, precise, hard threshold
 
Short description
+++++++++++++++++
 
Current-based leaky integrate-and-fire neuron with exponential-shaped
postsynaptic currents using regula falsi method for approximation of
threshold crossing
 
Description
+++++++++++
 
``iaf_psc_exp_ps`` is the "canonical" implementation of the leaky
integrate-and-fire model neuron with exponential postsynaptic currents
that uses the regula falsi method to approximate the timing of a threshold
crossing. This is the most exact implementation available.
 
The canonical implementation handles neuronal dynamics in a locally
event-based manner with in coarse time grid defined by the minimum
delay in the network, see :footcite:p:`Morrison2007a` :footcite:p:`Hanuschkin2010`. Incoming spikes are applied at the
precise moment of their arrival, while the precise time of outgoing
spikes is determined by regula falsi once a threshold crossing has
been detected. Return from refractoriness occurs precisely at spike
time plus refractory period.
 
This implementation is more complex than the plain iaf_psc_exp
neuron, but achieves much higher precision. In particular, it does not
suffer any binning of spike times to grid points. Depending on your
application, the canonical application with regula falsi may provide
superior overall performance given an accuracy goal; see :footcite:p:`Morrison2007a` :footcite:p:`Hanuschkin2010` for
details. Subthreshold dynamics are integrated using exact integration
between events :footcite:p:`Rotter1999`.
 
Please note that this node is capable of sending precise spike times
to target nodes (on-grid spike time and offset).
 
The iaf_psc_delta_ps neuron accepts connections transmitting
CurrentEvents. These events transmit stepwise-constant currents which
can only change at on-grid times.
 
.. note::
 
  If `tau_m` is very close to `tau_syn_ex` or `tau_syn_in`, the model
  will numerically behave as if `tau_m` is equal to `tau_syn_ex` or
  `tau_syn_in`, respectively, to avoid numerical instabilities.
 
  For implementation details see the
  `IAF Integration Singularity notebook <../model_details/IAF_Integration_Singularity.ipynb>`_.
 
For details about exact subthreshold integration, please see
:doc:`../neurons/exact-integration`.
 
Parameters
++++++++++
 
The following parameters can be set in the status dictionary.
 
==========  =====  ==========================================================
E_L         mV     Resting membrane potential
C_m         pF     Capacitance of the membrane
tau_m       ms     Membrane time constant
tau_syn_ex  ms     Excitatory synaptic time constant
tau_syn_in  ms     Inhibitory synaptic time constant
t_ref       ms     Duration of refractory period
V_th        mV     Spike threshold
I_e         pA     Constant input current
V_min       mV     Absolute lower value for the membrane potential
V_reset     mV     Reset value for the membrane potential
==========  =====  ==========================================================
 
References
++++++++++
 
.. footbibliography::
 
Sends
+++++
 
SpikeEvent
 
Receives
++++++++
 
SpikeEvent, CurrentEvent, DataLoggingRequest
 
See also
++++++++
 
iaf_psc_exp, iaf_psc_alpha_ps
 
Examples using this model
+++++++++++++++++++++++++
 
.. listexamples:: iaf_psc_exp_ps
 
EndUserDocs */
 
void register_iaf_psc_exp_ps( const std::string& name );
 
class iaf_psc_exp_ps : public ArchivingNode
{
public:
  iaf_psc_exp_ps();
 
  iaf_psc_exp_ps( const iaf_psc_exp_ps& );
 
  using Node::handle;
  using Node::handles_test_event;
 
  size_t send_test_event( Node&, size_t, synindex, bool ) override;
 
  size_t handles_test_event( SpikeEvent&, size_t ) override;
  size_t handles_test_event( CurrentEvent&, size_t ) override;
  size_t handles_test_event( DataLoggingRequest&, size_t ) override;
 
  void handle( SpikeEvent& ) override;
  void handle( CurrentEvent& ) override;
  void handle( DataLoggingRequest& ) override;
 
  bool
  is_off_grid() const override
  {
    return true;
  }
 
  void get_status( Dictionary& ) const override;
  void set_status( const Dictionary& ) override;
 
  double threshold_distance( double t_step ) const;
 
private:
  void init_buffers_() override;
  void pre_run_hook() override;
 
  void update( Time const& origin, const long from, const long to ) override;
 
  // The next two classes need to be friends to access the State_ class/member
  friend class RecordablesMap< iaf_psc_exp_ps >;
  friend class UniversalDataLogger< iaf_psc_exp_ps >;
 
  void propagate_( const double dt );
 
  void emit_spike_( const Time& origin, const long lag, const double t0, const double dt );
 
  void emit_instant_spike_( const Time& origin, const long lag, const double spike_offset );
 
  IAFPropagatorExp propagator_ex_;
  IAFPropagatorExp propagator_in_;
 
  // ----------------------------------------------------------------
 
  struct Parameters_
  {
    double tau_m_;
 
    double tau_ex_;
 
    double tau_in_;
 
    double c_m_;
 
    double t_ref_;
 
    double E_L_;
 
    double I_e_;
 
    double U_th_;
 
    double U_min_;
 
    double U_reset_;
 
    Parameters_();  
 
    void get( Dictionary& ) const;  
 
    double set( const Dictionary&, Node* node );
  };
 
  // ----------------------------------------------------------------
 
  struct State_
  {
    double y0_;     
    double y1_ex_;  
    double y1_in_;  
    double y2_;     
 
    bool is_refractory_;        
    long last_spike_step_;      
    double last_spike_offset_;  
 
    State_();  
 
    void get( Dictionary&, const Parameters_& ) const;
 
    void set( const Dictionary&, const Parameters_&, double, Node* );
  };
 
  // ----------------------------------------------------------------
 
  struct Buffers_
  {
    Buffers_( iaf_psc_exp_ps& );
    Buffers_( const Buffers_&, iaf_psc_exp_ps& );
 
    SliceRingBuffer events_;
    RingBuffer currents_;
 
    UniversalDataLogger< iaf_psc_exp_ps > logger_;
  };
 
  // ----------------------------------------------------------------
 
  struct Variables_
  {
    double h_ms_;            
    long refractory_steps_;  
    double expm1_tau_m_;     
    double exp_tau_ex_;      
    double exp_tau_in_;      
    double P20_;             
    double P21_in_;          
    double P21_ex_;          
    double y0_before_;       
    double y1_ex_before_;    
    double y1_in_before_;    
    double y2_before_;       
  };
 
  // Access functions for UniversalDataLogger -------------------------------
 
  double
  get_V_m_() const
  {
    return S_.y2_ + P_.E_L_;
  }
 
  // ----------------------------------------------------------------
 
  Parameters_ P_;
  State_ S_;
  Variables_ V_;
  Buffers_ B_;
  static RecordablesMap< iaf_psc_exp_ps > recordablesMap_;
};
 
inline size_t
iaf_psc_exp_ps::send_test_event( Node& target, size_t receptor_type, synindex, bool )
{
  SpikeEvent e;
  e.set_sender( *this );
  return target.handles_test_event( e, receptor_type );
}
 
inline size_t
iaf_psc_exp_ps::handles_test_event( SpikeEvent&, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return 0;
}
 
inline size_t
iaf_psc_exp_ps::handles_test_event( CurrentEvent&, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return 0;
}
 
inline size_t
iaf_psc_exp_ps::handles_test_event( DataLoggingRequest& dlr, size_t receptor_type )
{
  if ( receptor_type != 0 )
  {
    throw UnknownReceptorType( receptor_type, get_name() );
  }
  return B_.logger_.connect_logging_device( dlr, recordablesMap_ );
}
 
inline void
iaf_psc_exp_ps::get_status( Dictionary& d ) const
{
  P_.get( d );
  S_.get( d, P_ );
  ArchivingNode::get_status( d );
 
  d[ names::recordables ] = recordablesMap_.get_list();
}
 
inline void
iaf_psc_exp_ps::set_status( const Dictionary& d )
{
  Parameters_ ptmp = P_;                        // temporary copy in case of errors
  const double delta_EL = ptmp.set( d, this );  // throws if BadProperty
  State_ stmp = S_;                             // temporary copy in case of errors
  stmp.set( d, ptmp, delta_EL, this );          // throws if BadProperty
 
  // We now know that (ptmp, stmp) are consistent. We do not
  // write them back to (P_, S_) before we are also sure that
  // the properties to be set in the parent class are internally
  // consistent.
  ArchivingNode::set_status( d );
 
  // if we get here, temporaries contain consistent set of properties
  P_ = ptmp;
  S_ = stmp;
}
 
}  // namespace
 
#endif  // IAF_PSC_EXP_PS_H