PopulationView

PopulationView(self, population, ranks, geometry=None)

Subset of a Population.

A list of ranks can be passed, but population views are usually created through slicing:

pop = net.create(1000, neuron)

E = pop[:800] # ann.PopulationView(pop, range(800))
I = pop[800:] # ann.PopulationView(pop, range(800, 1000))

Parameters

Name	Type	Description	Default
population		population object	required
ranks		list or numpy array containing the ranks of the selected neurons.	required
geometry		a geometry for the Populationview (optional)	None

Attributes

Name	Description
population	Original population.
ranks	Array of ranks in the PopulationView.
geometry	Geometry of the PopulationView (optional).
size	Size of the PopulationView (number of neurons).
targets	List of targets connected to the population.
name	Name of the original population.
attributes	Äist of attributes of the original population.
variables	List of variables of the original population.
parameters	List of constants of the original population.

Methods

Name	Description
rank_from_coordinates	Returns the rank of a neuron based on coordinates.
coordinates_from_rank	Returns the coordinates of a neuron based on its rank.
get	Returns the parameter/variable value.
set	Updates the neurons’ parameter/variable values.
sum	Returns the array of weighted sums corresponding to the target:

rank_from_coordinates

rank_from_coordinates(coord, local=False)

Returns the rank of a neuron based on coordinates.

When local is False (default), the coordinates are relative to the ORIGINAL population, not the PopulationView.

When local is True, the coordinates are interpreted relative to the geometry of the PopulationView if available. When you add two population views, the geometry is lost and the method will return an error.

The rank is relative to the original population. Iterate over len(pop) otherwise.

Parameters

Name	Type	Description	Default
coord	tuple	coordinate tuple, can be multidimensional.	required
local	bool	whether the coordinates are local to the PopulationView or not.	False

coordinates_from_rank

coordinates_from_rank(rank, local=False)

Returns the coordinates of a neuron based on its rank.

When local is False (default), the coordinates are relative to the ORIGINAL population, not the PopulationView.

When local is True, the coordinates are interpreted relative to the geometry of the PopulationView if available. When you add two population views, the geometry is lost and the method will return an error.

The rank is relative to the original population. Iterate over len(pop) otherwise.

Parameters

Name	Type	Description	Default
rank	int	rank of the neuron in the original population.	required
local	bool	whether the coordinates are local to the PopulationView or not.	False

get

get(name)

Returns the parameter/variable value.

Parameters

Name	Type	Description	Default
name		name of the parameter/variable.	required

set

set(value)

Updates the neurons’ parameter/variable values.

Warning: If you modify the value of a global parameter, this will be the case for ALL neurons of the population, not only the subset.

Parameters

Name	Type	Description	Default
value	dict	dictionary of parameters/variables to be updated for the corresponding subset of neurons. It can be a single value or a list/1D array of the same size as the PopulationView.	required

sum

sum(target)

Returns the array of weighted sums corresponding to the target:

excitatory = pop[:50].sum('exc')

For spiking networks, this is equivalent to accessing the conductances directly::

excitatory = pop[:50].g_exc

If no incoming projection has the given target, the method returns zeros.

Parameters

Name	Type	Description	Default
target	str	the target.	required