- remove reduce_invertible. It is subsumed by reduce_uncstr(2)
- introduce a simplifier for reduce_unconstrained. It uses reference counting to deal with inefficiency bug of legacy reduce_uncstr. It decomposes theory plugins into expr_inverter.
reduce_invertible is a tactic used in most built-in scenarios. It is useful for removing subterms that can be eliminated using "cheap" quantifier elimination. Specifically variables that occur only once can be removed in many cases by computing an expression that represents the effect computing a value for the eliminated occurrence.
The theory plugins for variable elimination are very partial and should be augmented by extensions, esp. for the case of bit-vectors where the invertibility conditions are thoroughly documented by Niemetz and Preiner.
the solve_eqs_tactic is to be replaced by a re-implementation that uses solve_eqs in the simplifiers directory.
The re-implementation should address efficiency issues with the previous code.
At this point it punts on low level proofs. The plan is to use coarser
dependency tracking instead of low level proofs for pre-processing. Dependencies can be converted into a proof hint representation that can be checked using a stronger checker.
* Memory leak in .NET user-propagator
The user-propagator object has to be manually disposed (IDisposable), otherwise it stays in memory forever, as it cannot be garbage collected automatically
* Throw an exception if variable passed to decide is already assigned instead of running in an assertion violation
* Added limit to "visit" to allow detecting multiple visits
* Putting visit in a separate class
(Reason: We will probably need two of them in the sat::solver)
* Bugfix
* Memory leak in .NET user-propagator
The user-propagator object has to be manually disposed (IDisposable), otherwise it stays in memory forever, as it cannot be garbage collected automatically
* Throw an exception if variable passed to decide is already assigned instead of running in an assertion violation
* Added 64-bit "1" counting
