nemo::Network Class Reference

Inherits nemo::ReadableNetwork.

Public Member Functions
unsigned	addNeuronType (const std::string &name)
	Register a new neuron type with the network.
void	addNeuron (unsigned type, unsigned idx, unsigned nargs, const float args[])
	Add a neuron to the network.
void	addNeuron (unsigned idx, float a, float b, float c, float d, float u, float v, float sigma)
	Add a single Izhikevich neuron to the network.
void	setNeuron (unsigned idx, unsigned nargs, const float args[])
void	setNeuron (unsigned idx, float a, float b, float c, float d, float u, float v, float sigma)
float	getNeuronParameter (unsigned neuron, unsigned parameter) const
float	getNeuronState (unsigned neuron, unsigned var) const
void	setNeuronParameter (unsigned neuron, unsigned parameter, float value)
void	setNeuronState (unsigned neuron, unsigned var, float value)
unsigned	getSynapseTarget (const synapse_id &) const
unsigned	getSynapseDelay (const synapse_id &) const
float	getSynapseWeight (const synapse_id &) const
unsigned char	getSynapsePlastic (const synapse_id &) const
const std::vector< synapse_id > &	getSynapsesFrom (unsigned neuron)
unsigned	maxDelay () const
unsigned	neuronCount () const

---

Detailed Description

Networks are constructed by adding individual neurons, and single or groups of synapses to the network. Neurons are given indices (from 0) which should be unique for each neuron. When adding synapses the source or target neurons need not necessarily exist yet, but should be defined before the network is finalised.

---

Member Function Documentation

unsigned nemo::Network::addNeuronType

(

const std::string &

name

)

Register a new neuron type with the network.

Parameters:

name

canonical name of the neuron type. The neuron type data is loaded from a plugin configuration file of the same name.

Returns:

index of the the neuron type, to be used when adding neurons.

This function must be called before neurons of the specified type can be added to the network.

void nemo::Network::addNeuron	(	unsigned	type,
		unsigned	idx,
		unsigned	nargs,
		const float	args[]
	)

Add a neuron to the network.

Parameters:

	type	index of the neuron type, as returned by addNeuronType
	idx	index of the neuron
	nargs	length of args
	args	parameters and state variables of the neuron (in that order)

Precondition:

The parameter and state arrays must have the dimensions matching the neuron type represented by type.

void nemo::Network::addNeuron	(	unsigned	idx,
		float	a,
		float	b,
		float	c,
		float	d,
		float	u,
		float	v,
		float	sigma
	)

Add a single Izhikevich neuron to the network.

The neuron uses the Izhikevich neuron model. See E. M. Izhikevich "Simple model of spiking neurons", IEEE Trans. Neural Networks, vol 14, pp 1569-1572, 2003 for a full description of the model and the parameters.

Parameters:

	idx	Neuron index. This should be unique
	a	Time scale of the recovery variable u
	b	Sensitivity to sub-threshold fluctutations in the membrane potential v
	c	After-spike reset value of the membrane potential v
	d	After-spike reset of the recovery variable u
	u	Initial value for the membrane recovery variable
	v	Initial value for the membrane potential
	sigma	Parameter for a random gaussian per-neuron process which generates random input current drawn from an N(0,sigma) distribution. If set to zero no random input current will be generated.

Deprecated:

in favour of the generic Network::addNeuron function

void nemo::Network::setNeuron	(	unsigned	idx,
		unsigned	nargs,
		const float	args[]
	)

Set an existing neuron

Parameters:

	idx	index of the neuron, as used when calling addNeuron
	nargs	length of args
	args	parameters and state variables of the neuron (in that order)

Precondition:

The parameter and state arrays must have the dimensions matching the neuron type specified when the neuron was first added.

void nemo::Network::setNeuron	(	unsigned	idx,
		float	a,
		float	b,
		float	c,
		float	d,
		float	u,
		float	v,
		float	sigma
	)

Change parameters/state variables of a single existing Izhikevich-type neuron

The parameters are the same as for nemo::Network::addNeuron

Deprecated:

in favour of the generic nemo::Network::setNeuron function

float nemo::Network::getNeuronParameter	(	unsigned	neuron,
		unsigned	parameter
	)			const

Get a single parameter for a single neuron

Parameters:

	neuron	neuron index
	parameter	parameter index

Returns:

parameter with index parameter.

For the Izhikevich model the parameter indices are 0=a, 1=b, 2=c, 3=d, 4=sigma.

float nemo::Network::getNeuronState	(	unsigned	neuron,
		unsigned	var
	)			const

Get a single state variable for a single neuron

Parameters:

	neuron	neuron index
	var	variable index

Returns:

state variable with index var.

For the Izhikevich model the variable indices are 0=u, 1=v.

void nemo::Network::setNeuronParameter	(	unsigned	neuron,
		unsigned	parameter,
		float	value
	)

Change a single parameter for an existing neuron

Parameters:

	neuron	neuron index
	parameter	parameter index
	value	new value of the state variable

For the Izhikevich model the parameter indices are 0=a, 1=b, 2=c, 3=d, 4=sigma.

void nemo::Network::setNeuronState	(	unsigned	neuron,
		unsigned	var,
		float	value
	)

Change a single state variable for an existing neuron

Parameters:

	neuron	neuron index
	var	state variable index
	value	new value of the state variable

For the Izhikevich model variable indices 0=u, 1=v.

unsigned nemo::Network::getSynapseTarget

(

const synapse_id &

)

const [virtual]

Returns:

target neuron id for a synapse

Implements nemo::ReadableNetwork.

unsigned nemo::Network::getSynapseDelay

(

const synapse_id &

)

const [virtual]

Returns:

conductance delay for a synapse

Implements nemo::ReadableNetwork.

float nemo::Network::getSynapseWeight

(

const synapse_id &

)

const [virtual]

Returns:

weight for a synapse

Implements nemo::ReadableNetwork.

unsigned char nemo::Network::getSynapsePlastic

(

const synapse_id &

)

const [virtual]

Returns:

plasticity status for a synapse

Implements nemo::ReadableNetwork.

const std::vector<synapse_id>& nemo::Network::getSynapsesFrom

(

unsigned

neuron

)

[virtual]

Returns:

vector of synapse ids for all synapses with the given source neuron

The vector reference is valid until the next call to this function.

Implements nemo::ReadableNetwork.

unsigned nemo::Network::maxDelay

(

)

const

Returns:

maximum delay (in milliseconds) in the network

unsigned nemo::Network::neuronCount

(

)

const

Returns:

maximum delay (in milliseconds) in the network