ArrayVariable class
(Shortest import: from brian2.core.variables import ArrayVariable)
- class brian2.core.variables.ArrayVariable(name, owner, size, device, dimensions=Dimension(), dtype=None, constant=False, scalar=False, read_only=False, dynamic=False, unique=False)[source]
Bases:
Variable
An object providing information about a model variable stored in an array (for example, all state variables). Most of the time
Variables.add_array
should be used instead of instantiating this class directly.- Parameters:
name : ‘str’
The name of the variable. Note that this refers to the original name in the owning group. The same variable may be known under other names in other groups (e.g. the variable
v
of aNeuronGroup
is known asv_post
in aSynapse
connecting to the group).dimensions :
Dimension
, optionalThe physical dimensions of the variable
owner :
Nameable
The object that “owns” this variable, e.g. the
NeuronGroup
orSynapses
object that declares the variable in its model equations.size : int
The size of the array
device :
Device
The device responsible for the memory access.
dtype :
dtype
, optionalThe dtype used for storing the variable. If none is given, defaults to core.default_float_dtype.
constant : bool, optional
Whether the variable’s value is constant during a run. Defaults to
False
.scalar : bool, optional
Whether this array is a 1-element array that should be treated like a scalar (e.g. for a single delay value across synapses). Defaults to
False
.read_only : bool, optional
Whether this is a read-only variable, i.e. a variable that is set internally and cannot be changed by the user. Defaults to
False
.unique : bool, optional
Whether the values in this array are all unique. This information is only important for variables used as indices and does not have to reflect the actual contents of the array but only the possibility of non-uniqueness (e.g. synaptic indices are always unique but the corresponding pre- and post-synaptic indices are not). Defaults to
False
.
Attributes
Another variable, on which the write is conditioned (e.g. a variable denoting the absence of refractoriness).
The
Device
responsible for memory access.The size of this variable.
Wether all values in this arrays are necessarily unique (only relevant for index variables).
Methods
get_addressable_value
(name, group)Get the value (without units) of this variable in a form that can be indexed in the context of a group.
get_addressable_value_with_unit
(name, group)Get the value (with units) of this variable in a form that can be indexed in the context of a group.
get_len
()Get the length of the value associated with the variable or
0
for a scalar variable.Return the value associated with the variable (without units).
item
()set_value
(value)Set the value associated with the variable.
Details
- conditional_write
Another variable, on which the write is conditioned (e.g. a variable denoting the absence of refractoriness)
- device
The
Device
responsible for memory access.
- size
The size of this variable.
- unique
Wether all values in this arrays are necessarily unique (only relevant for index variables).
- get_addressable_value(name, group)[source]
Get the value (without units) of this variable in a form that can be indexed in the context of a group. For example, if a postsynaptic variable
x
is accessed in a synapseS
asS.x_post
, the synaptic indexing scheme can be used.- Parameters:
name : str
The name of the variable
group :
Group
The group providing the context for the indexing. Note that this
group
is not necessarily the same asVariable.owner
: a variable owned by aNeuronGroup
can be indexed in a different way if accessed via aSynapses
object.- Returns:
variable : object
The variable in an indexable form (without units).
- get_addressable_value_with_unit(name, group)[source]
Get the value (with units) of this variable in a form that can be indexed in the context of a group. For example, if a postsynaptic variable
x
is accessed in a synapseS
asS.x_post
, the synaptic indexing scheme can be used.- Parameters:
name : str
The name of the variable
group :
Group
The group providing the context for the indexing. Note that this
group
is not necessarily the same asVariable.owner
: a variable owned by aNeuronGroup
can be indexed in a different way if accessed via aSynapses
object.- Returns:
variable : object
The variable in an indexable form (with units).
- get_len()[source]
Get the length of the value associated with the variable or
0
for a scalar variable.