tbnpy.variable

Overview

The Variable class stores metadata about a Bayesian-network variable (name, domain) and provides helper methods for working with composite states (sets of basic states represented in a compact index form).

Quick start

from tbnpy.variable import Variable

# Discrete variable: values define the ordered basic states
v = Variable("damage_state", values=["none", "minor", "major"])

# Example: the composite state {1, 2} (i.e., {"minor","major"})
st = v.get_state({1, 2})
S  = v.get_set(st)

Public API

Variable

class Variable(name: str, values=None)

Manage information about a variable.

Parameters

name

Variable name used as an identifier (hashing, ordering, printing).

values

Domain specification.

  • Discrete variable: a list/numpy.ndarray of labels (states are indexed as 0, 1, 2, ... in that order).

  • Continuous variable: a tuple (min, max) where bounds may be finite numbers or infinities (e.g. (-torch.inf, torch.inf)).

  • None: allowed; indicates the domain is unspecified.

Attributes

namestr

Variable name.

valueslist | tuple | None

Domain specification as described above.

Notes

Ordering tip: when applicable, prefer an ordering where lower indices represent worse outcomes, because some modules may assume this convention (e.g., ["failure", "survival"] so that 0 < 1).

Properties

Variable.name: str

Variable name.

Variable.values: list | tuple | None

Variable domain specification (discrete labels or continuous bounds).

Composite-state helpers

The following methods work with composite states. A composite state represents a set of basic (discrete) states. Internally, the module uses a deterministic ordering over all non-empty subsets (e.g., all 1-element subsets, then all 2-element subsets, …, up to the full set).

Variable.get_state(state_set: set) → int

Convert a set of basic-state indices to its composite-state index.

Parameters
state_set

A Python set of integer indices into values (e.g., {0}, {1, 2}).

Returns
int

Composite-state index representing the same subset.

Notes

  • state_set must be a non-empty set.

  • This method assumes a discrete variable (values is list/ndarray).

Examples
v = Variable("x", ["low", "med", "high"])
v.get_state({1, 2})  # -> composite index for {"med","high"}
Variable.get_set(state: int) → set

Convert a composite-state index back to the corresponding set of basic-state indices.

Parameters
state

Composite-state index (non-negative integer).

Returns
set

A set of basic-state indices (e.g., {0, 2}).

Variable.get_state_from_vector(vector) → int

Convert a binary indicator vector to a composite-state index.

Parameters
vector

A 1D list/array of length len(values) with entries in {0,1}. A value of 1 indicates that the corresponding basic state is included in the subset.

Returns
int

Composite-state index, or -1 if the vector is all zeros (empty set).

Hidden helpers (intentionally omitted)

To keep this page focussed on the commonly used API, the following lower-level helper functions are intentionally omitted from this page:

  • get_Cbin_to_Cst

  • get_Cst_to_Cbin

  • build_state_to_binary_lookup

  • build_bitmask_to_state_lookup

(They remain available in the module, but are treated as internal/advanced utilities.)