Value

class liesel.model.nodes.Value(value, _name='')

Bases: Node

A Node subclass that holds constant values.

Since the information represented by a value node does not change, it is always up-to-date. A common usecase for value nodes is to cache computed values.

• By default, value nodes will appear in the node graph created by viz.plot_nodes(), but they will not appear in the model graph created by viz.plot_vars().

• You can wrap a value node in a Var to make it appear in the model graph.

Parameters:

• value (Any) – The value of the node.

• _name (str) – The name of the node. If you do not specify a name, a unique name will be automatically generated upon initialization of a Model. (default: '')

See also

Calc

A node representing a general calculation/operation in JAX or Python.

Dist

A node representing a tensorflow_probability Distribution.

Var

A variable in a statistical model, typically with a probability distribution.

param

A helper function to initialize a Var as a model parameter.

obs

A helper function to initialize a Var as an observed variable.

Examples

A simple constant node representing a constant value without a name:

>>> nameless_node = lsl.Value(1.0)
>>> nameless_node
Value(name="")

Adding this node to a model leads to an automatically generated name:

>>> model = lsl.GraphBuilder().add(nameless_node).build_model()
>>> nameless_node
Value(name="n0")

A constant node with a name:

>>> node = lsl.Value(1.0, _name="my_name")
>>> node
Value(name="my_name")

Methods

add_inputs(*inputs, **kwinputs)	Adds non-keyword and keyword input nodes to the existing ones.
all_input_nodes()	Returns all non-keyword and keyword input nodes as a unique tuple.
all_output_nodes()	Returns all output nodes as a unique tuple.
clear_state()	Clears the state of the node.
flag_outdated()	Stops the recursion setting outdated flags.
set_inputs(*inputs, **kwinputs)	Sets the non-keyword and keyword input nodes.
update()	Does nothing.

Attributes

groups	The groups that this node is a part of.
inputs	The non-keyword input nodes.
kwinputs	The keyword input nodes.
model	The model the node is part of.
name	The name of the node.
needs_seed	Whether the node needs a seed / PRNG key.
outdated	Whether the node is outdated.
outputs	The output nodes.
state	The state of the node.
value	The value of the node.
var	The variable the node is part of.
monitor	Whether the node should be monitored by an inference algorithm.