souffle::ram::transform::ReorderConditionsTransformer Class Reference

Reorders conjunctive terms depending on cost, i.e., cheap terms should be executed first. More...

#include <ReorderConditions.h>

Inheritance diagram for souffle::ram::transform::ReorderConditionsTransformer:

Collaboration diagram for souffle::ram::transform::ReorderConditionsTransformer:

Public Member Functions
std::string	getName () const override
	@Brief get name of the transformer More...
bool	reorderConditions (Program &program)
	Reorder conjunctive terms in filter operations. More...
Public Member Functions inherited from souffle::ram::transform::Transformer
bool	apply (TranslationUnit &translationUnit)
	@Brief apply the transformer to a translation unit @Param translationUnit that will be transformed. More...
virtual	~Transformer ()=default

Protected Member Functions
bool	transform (TranslationUnit &translationUnit) override
	@Brief transform the translation unit / used by apply @Param translationUnit that will be transformed. More...

Protected Attributes
analysis::ComplexityAnalysis *	rca {nullptr}

Detailed Description

Reorders conjunctive terms depending on cost, i.e., cheap terms should be executed first.

For example ..

QUERY
 ...
  IF C(1) /\ C(2) /\ ... /\ C(N) then
   ...

will be rewritten to

QUERY
 ...
  IF C(i(1)) /\ C(i(2)) /\ ... /\ C(i(N)) then
    ...

where C(i(1)) <= C(i(2)) <= .... <= C(i(N)).

The terms are sorted according to their complexity class.

Definition at line 58 of file ReorderConditions.h.

Member Function Documentation

getName()

std::string souffle::ram::transform::ReorderConditionsTransformer::getName ( ) const

inlineoverridevirtual

@Brief get name of the transformer

Implements souffle::ram::transform::Transformer.

Definition at line 60 of file ReorderConditions.h.

         :
    analysis::ComplexityAnalysis* rca{nullptr};

reorderConditions()

bool souffle::ram::transform::ReorderConditionsTransformer::reorderConditions

(

Program &

program

)

Reorder conjunctive terms in filter operations.

Parameters

program

Program that is transformed

Returns

Flag showing whether the program has been changed by the transformation

Definition at line 36 of file ReorderConditions.cpp.

                                                                          {
                const Condition* condition = &filter->getCondition();
                VecOwn<Condition> sortedConds;
                VecOwn<Condition> condList = toConjunctionList(condition);
                for (auto& cond : condList) {
                    sortedConds.emplace_back(cond->clone());
                }
                std::sort(sortedConds.begin(), sortedConds.end(), [&](Own<Condition>& a, Own<Condition>& b) {
                    return rca->getComplexity(a.get()) < rca->getComplexity(b.get());
                });
 
                if (!std::equal(sortedConds.begin(), sortedConds.end(), condList.begin(),
                            [](Own<Condition>& a, Own<Condition>& b) { return *a == *b; })) {
                    changed = true;
                    node = mk<Filter>(Own<Condition>(toCondition(sortedConds)),
                            souffle::clone(&filter->getOperation()));
                }
            }
            node->apply(makeLambdaRamMapper(filterRewriter));
            return node;
        };
        const_cast<Query*>(&query)->apply(makeLambdaRamMapper(filterRewriter));
    });
    return changed;
}
 
}  // namespace souffle::ram::transform

References b, souffle::clone(), souffle::filter(), souffle::ram::toCondition(), and souffle::ram::toConjunctionList().

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transform()

bool souffle::ram::transform::ReorderConditionsTransformer::transform ( TranslationUnit &  translationUnit )

inlineoverrideprotectedvirtual

@Brief transform the translation unit / used by apply @Param translationUnit that will be transformed.

@Return flag reporting whether the RAM program has changed

Implements souffle::ram::transform::Transformer.

Definition at line 75 of file ReorderConditions.h.

Field Documentation

rca

analysis::ComplexityAnalysis* souffle::ram::transform::ReorderConditionsTransformer::rca {nullptr}

protected

Definition at line 73 of file ReorderConditions.h.

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The documentation for this class was generated from the following files:

• ram/transform/ReorderConditions.h
• ram/transform/ReorderConditions.cpp