Nodes#

Construct calculations, graph nodes, and reusable model inputs.

`Calc`	A `Node` subclass that calculates its value based on its inputs nodes.
`Node`	A node of a computational graph that can cache its value.
`Value`	A `Node` subclass that holds constant values.
`PIT`	A weak variable evaluating a probability integral transform (PIT).
`TransientCalc`	A transient calculator node that does not cache its value.
`TransientDist`	A transient distribution node that does not cache its value.
`TransientIdentity`	A transient identity node that does not cache its value.
`TransientNode`	A node that does not cache its value.
`InputGroup`	A node that groups its inputs for another node.
`GraphBuilder`	A graph builder, used to set up a `Model`.