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Implemented simplification of directly nested n-ary expressions of the same type.

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This commit is contained in:
Patrick Lühne 2016-09-05 00:37:43 +02:00
parent 79d449d0df
commit 263b611a7b
4 changed files with 70 additions and 10 deletions
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1
include/plasp/pddl/Expression.h
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@ -112,6 +112,7 @@ class Expression
ExpressionPointer normalized();
virtual ExpressionPointer reduced();
virtual ExpressionPointer negationNormalized();
virtual ExpressionPointer simplified();
ExpressionPointer negated();
virtual void print(std::ostream &ostream) const = 0;

37
include/plasp/pddl/expressions/NAry.h
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@ -35,6 +35,7 @@ class NAry: public ExpressionCRTP<Derived>
ExpressionPointer reduced() override;
ExpressionPointer negationNormalized() override;
ExpressionPointer simplified() override;
void print(std::ostream &ostream) const override;
@ -145,19 +146,41 @@ inline ExpressionPointer NAry<Derived>::negationNormalized()
m_arguments[i] = m_arguments[i]->negationNormalized();
}
/*// Unify same-type children
for (size_t i = 0; i < m_arguments.size(); i++)
return this;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
template<class Derived>
inline ExpressionPointer NAry<Derived>::simplified()
{
// Associate same-type children, such as (a && (b && c)) == (a && b && c)
for (size_t i = 0; i < m_arguments.size();)
{
m_arguments[i] = m_arguments[i]->simplified();
if (m_arguments[i]->expressionType() != Derived::ExpressionType)
{
i++;
continue;
}
auto &nAryExpression = dynamic_cast<Derived &>(*m_arguments[i]);
auto child = m_arguments[i];
auto &nAryExpression = dynamic_cast<Derived &>(*child);
m_arguments.reserve(m_arguments.size() + nAryExpression.arguments().size());
BOOST_ASSERT(!nAryExpression.arguments().empty());
m_arguments.emplace_back(nAryExpression.arguments());
m_arguments.erase(const_iterator __position)
}*/
// Remove former child by replacing it with the first one of the child
m_arguments[i] = nAryExpression.arguments().front();
// Reserve space for new arguments
m_arguments.reserve(m_arguments.size() + nAryExpression.arguments().size() - 1);
// Copy all but first element
m_arguments.insert(m_arguments.end(), nAryExpression.arguments().begin() + 1, nAryExpression.arguments().end());
}
// TODO: recognize tautologies
return this;
}

9
src/plasp/pddl/Expression.cpp
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@ -26,7 +26,7 @@ namespace pddl
ExpressionPointer Expression::normalized()
{
return reduced()->negationNormalized();
return reduced()->negationNormalized()->simplified();
}
////////////////////////////////////////////////////////////////////////////////////////////////////
@ -45,6 +45,13 @@ ExpressionPointer Expression::negationNormalized()
////////////////////////////////////////////////////////////////////////////////////////////////////
ExpressionPointer Expression::simplified()
{
return this;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
ExpressionPointer Expression::negated()
{
if (expressionType() == Type::Not)

33
tests/TestPDDLNormalization.cpp
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@ -10,7 +10,7 @@ using namespace plasp::pddl;
////////////////////////////////////////////////////////////////////////////////////////////////////
TEST(PDDLNormalizationTests, Reduced)
TEST(PDDLNormalizationTests, Reduce)
{
auto n1 = expressions::NotPointer(new expressions::Not);
auto n2 = expressions::NotPointer(new expressions::Not);
@ -38,6 +38,36 @@ TEST(PDDLNormalizationTests, Reduced)
////////////////////////////////////////////////////////////////////////////////////////////////////
TEST(PDDLNormalizationTests, Simplify)
{
auto a1 = expressions::AndPointer(new expressions::And);
auto a2 = expressions::AndPointer(new expressions::And);
auto o1 = expressions::OrPointer(new expressions::Or);
auto o2 = expressions::OrPointer(new expressions::Or);
a1->addArgument(new expressions::Dummy("a"));
a1->addArgument(new expressions::Dummy("b"));
a1->addArgument(a2);
a2->addArgument(new expressions::Dummy("c"));
a2->addArgument(new expressions::Dummy("d"));
a2->addArgument(o1);
o1->addArgument(new expressions::Dummy("e"));
o1->addArgument(new expressions::Dummy("f"));
o1->addArgument(o2);
o2->addArgument(new expressions::Dummy("g"));
o2->addArgument(new expressions::Dummy("h"));
std::stringstream output;
a1->simplified()->print(output);
ASSERT_EQ(output.str(), "(and (a) (b) (c) (d) (or (e) (f) (g) (h)))");
}
////////////////////////////////////////////////////////////////////////////////////////////////////
TEST(PDDLNormalizationTests, Implication)
{
auto i = expressions::ImplyPointer(new expressions::Imply);
@ -85,7 +115,6 @@ TEST(PDDLNormalizationTests, DeMorganNegativeConjunction)
ASSERT_EQ(output.str(), "(or (not (a)) (not (b)) (not (c)))");
}
////////////////////////////////////////////////////////////////////////////////////////////////////
TEST(PDDLNormalizationTests, DeMorganNegativeDisjunction)