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Code Issues 15 Releases 21 Activity

Extend integer variable detection

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If making a variable noninteger turns the entire formula obtained from
completion true, we can drop that statement and conclude that the
variable is integer.
This commit is contained in:
Patrick Lühne 2018-04-21 17:10:24 +02:00
parent 9c792ff079
commit 28dbd407e2
Signed by: patrick
GPG Key ID: 05F3611E97A70ABF
1 changed files with 36 additions and 0 deletions
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36
src/anthem/IntegerVariableDetection.cpp
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@ -565,6 +565,39 @@ struct CheckIfQuantifiedFormulaFalseFunctor
////////////////////////////////////////////////////////////////////////////////////////////////////
struct CheckIfCompletedFormulaTrueFunctor
{
OperationResult operator()(ast::VariableDeclaration &variableDeclaration,
ast::Formula &, ast::Formula &completedFormula, VariableDomainMap &variableDomainMap)
{
if (variableDeclaration.domain != ast::Domain::Unknown)
return OperationResult::Unchanged;
clearVariableDomainMap(variableDomainMap);
auto result = evaluate(completedFormula, variableDomainMap);
if (result == EvaluationResult::Error || result == EvaluationResult::True)
return OperationResult::Unchanged;
// As a hypothesis, make the parameter’s domain noninteger
variableDomainMap[&variableDeclaration] = ast::Domain::General;
result = evaluate(completedFormula, variableDomainMap);
if (result == EvaluationResult::Error || result == EvaluationResult::True)
{
// If making the variable noninteger leads to a false or erroneous result, it’s proven to be integer
variableDeclaration.domain = ast::Domain::Integer;
return OperationResult::Changed;
}
return OperationResult::Unchanged;
}
};
////////////////////////////////////////////////////////////////////////////////////////////////////
// Assumes the completed formulas to be in translated but not simplified form.
// That is, completed formulas are either variable-free or universally quantified
void detectIntegerVariables(std::vector<ast::Formula> &completedFormulas)
@ -581,6 +614,9 @@ void detectIntegerVariables(std::vector<ast::Formula> &completedFormulas)
if (completedFormula.accept(ForEachVariableDeclarationVisitor<CheckIfQuantifiedFormulaFalseFunctor>(), variableDomainMap) == OperationResult::Changed)
operationResult = OperationResult::Changed;
if (completedFormula.accept(ForEachVariableDeclarationVisitor<CheckIfCompletedFormulaTrueFunctor>(), completedFormula, variableDomainMap) == OperationResult::Changed)
operationResult = OperationResult::Changed;
if (!completedFormula.is<ast::ForAll>())
continue;