IAFPropagator Class Reference

Exact integration voltage propagator for leaky integrate-and-fire models. More...

#include <iaf_propagator.h>

Inheritance diagram for IAFPropagator:

Public Member Functions
	IAFPropagator ()
	Empty constructor needed for initialization of buffers.
	IAFPropagator (double tau_syn, double tau_m, double c_m)

Protected Member Functions
std::tuple< double, double, double, double >	evaluate_P32_ (double h) const
	Compute propagator connecting I_syn to V_m and auxiliary quantities for given time interval.

Protected Attributes
double	tau_syn_
	Time constant of synaptic current in ms.
double	tau_m_
	Membrane time constant in ms.
double	c_m_
	Membrane capacitance in pF.
double	h_min_regular_
	Smallest h for which regular P31 case applies.
double	beta_
	(tau_syn * tau_m) / (tau_m - tau_syn)
double	gamma_
	beta_ / c_m
double	inv_tau_syn_
	1 / tau_syn
double	inv_tau_m_
	1 / tau_m
double	inv_c_m_
	1 / c_m
double	inv_beta_
	1 / beta

Static Protected Attributes
static constexpr double	NUMERICAL_STABILITY_FACTOR_ = 1e-7
	Scale factor for singularity test for P31 computation.

Detailed Description

Exact integration voltage propagator for leaky integrate-and-fire models.

This base class and its derived classes provide the propagator matrix elements connecting synaptic current to membrane potential. They handle the singularity at tau_m == tau_syn_* properly.

See also

<NEST_SOURCE>/doc/userdoc/model_details/IAF_Integration_Singularity.ipynb

Constructor & Destructor Documentation

IAFPropagator() [1/2]

IAFPropagator::IAFPropagator

(

)

Empty constructor needed for initialization of buffers.

IAFPropagator() [2/2]

IAFPropagator::IAFPropagator	(	double	tau_syn,
		double	tau_m,
		double	c_m
	)

Parameters

tau_syn	Time constant of synaptic current in ms
tau_m	Membrane time constant in ms
c_m	Membrane capacitance in pF

Member Function Documentation

evaluate_P32_()

std::tuple< double, double, double, double > IAFPropagator::evaluate_P32_ ( double  h ) const

protected

Compute propagator connecting I_syn to V_m and auxiliary quantities for given time interval.

This method computes all quantities common to alpha and exponential synaptic dynamics.

Note

Fourth return value is real-valued only in the singular limit and numerics::nan otherwise to avoid unnecessary computation of exp().

Parameters

h	time interval [ms]

Returns

tuple with P_VI, exp( -h / tau_syn_ ), expm1( -h / tau_m_ + h / tau_syn_ ), exp( -h / tau_m_ )

References numerics::expm1(), gamma_, inv_beta_, inv_c_m_, inv_tau_m_, inv_tau_syn_, and numerics::nan.

Referenced by IAFPropagatorExp::evaluate(), and IAFPropagatorAlpha::evaluate().

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Member Data Documentation

beta_

double IAFPropagator::beta_

protected

(tau_syn * tau_m) / (tau_m - tau_syn)

Referenced by IAFPropagatorAlpha::evaluate().

c_m_

double IAFPropagator::c_m_

protected

Membrane capacitance in pF.

gamma_

double IAFPropagator::gamma_

protected

beta_ / c_m

Referenced by IAFPropagatorAlpha::evaluate(), and evaluate_P32_().

h_min_regular_

double IAFPropagator::h_min_regular_

protected

Smallest h for which regular P31 case applies.

Referenced by IAFPropagatorAlpha::evaluate().

inv_beta_

double IAFPropagator::inv_beta_

protected

1 / beta

Referenced by evaluate_P32_().

inv_c_m_

double IAFPropagator::inv_c_m_

protected

1 / c_m

Referenced by IAFPropagatorAlpha::evaluate(), and evaluate_P32_().

inv_tau_m_

double IAFPropagator::inv_tau_m_

protected

1 / tau_m

Referenced by IAFPropagatorAlpha::evaluate(), and evaluate_P32_().

inv_tau_syn_

double IAFPropagator::inv_tau_syn_

protected

1 / tau_syn

Referenced by evaluate_P32_().

NUMERICAL_STABILITY_FACTOR_

constexpr double IAFPropagator::NUMERICAL_STABILITY_FACTOR_ = 1e-7

staticconstexprprotected

Scale factor for singularity test for P31 computation.

Regular case applies if h > NUMERICAL_STABILITY_FACTOR_ * tau_m^2 / |tau_m - tau_syn|

See IAF_Integration_Singularity for details.

tau_m_

double IAFPropagator::tau_m_

protected

Membrane time constant in ms.

tau_syn_

double IAFPropagator::tau_syn_

protected

Time constant of synaptic current in ms.

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The documentation for this class was generated from the following files:

• iaf_propagator.h
• iaf_propagator.cpp