omega 0.2.1

Symbolic algorithms for solving games of infinite duration.

About

A package of symbolic algorithms using binary decision diagrams (BDDs) for synthesizing implementations from temporal logic specifications. This is useful for designing systems, especially vehicles that carry humans.

• Synthesis algorithms for Moore or Mealy implementations of:

  • generalized Streett(1) specifications (known as GR(1))
  • generalized Rabin(1) specifications (counter-strategies to GR(1))
  • detection of trivial realizability in GR(1) specifications.

  See omega.games.gr1.

• Enumeration of state machines (as networkx graphs) from the synthesized symbolic implementations. See omega.games.enumeration.

• Facilities to simulate the resulting implementations with little and readable user code. See omega.steps.

• Code generation for the synthesized symbolic implementations. This code is correct-by-construction.

• First-order linear temporal logic (LTL) with rigid quantification and substitution. See omega.logic.lexyacc, omega.logic.ast, and omega.logic.syntax.

• Bitblaster of quantified integer arithmetic (integers -> bits). See omega.logic.bitvector.

• Translation from past to future LTL, using temporal testers. See omega.logic.past.

• Symbolic automata that manage first-order formulas by seamlessly using binary decision diagrams (BDDs) underneath. You can:

  • declare variables and constants
  • translate:
    1. formulas to BDDs and
    2. BDDs to minimal formulas via minimal covering
  • quantify
  • substitute
  • prime/unprime variables
  • get the support of predicates
  • pick satisfying assignments (or work with iterators)
  • define operators

  See omega.symbolic.temporal and omega.symbolic.fol for more details.

• Facilities to write symbolic fixpoint algorithms. See omega.symbolic.fixpoint and omega.symbolic.prime.

• Conversion from graphs annotated with formulas to temporal logic formulas. These graphs can help specify transition relations. The translation is in the spirit of predicate-action diagrams.

  See omega.symbolic.logicizer and omega.automata for more details.

• Enumeration and plotting of state predicates and actions represented as BDDs. See omega.symbolic.enumeration.

Documentation

In doc/doc.md.

Installation

pip install omega

or

python setup.py install

The package and its dependencies are pure Python.

For solving demanding games, install the Cython module dd.cudd that interfaces to CUDD. Instructions are available at dd.

License

BSD-3, see LICENSE file.