diff options
author | Morgan Deters <mdeters@gmail.com> | 2011-10-13 04:14:38 +0000 |
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committer | Morgan Deters <mdeters@gmail.com> | 2011-10-13 04:14:38 +0000 |
commit | 3cbb76ef86a769cfe3dac5976a14e1bc43c42ca6 (patch) | |
tree | e08efdc63abd663de4f5750db9326b69c79829e5 /src/prop/prop_engine.h | |
parent | 3a7aafccadbfa1543c435b7dfe4f53116224a11f (diff) |
Interruption, time-out, and deterministic time-out ("resource-out") features.
Details here: http://goedel.cims.nyu.edu/wiki/Meeting_Minutes_-_October_14,_2011#Resource.2Ftime_limiting_API
This will need more work, but it's a start.
Also implemented TheoryEngine::properPropagation().
Other minor things.
Diffstat (limited to 'src/prop/prop_engine.h')
-rw-r--r-- | src/prop/prop_engine.h | 146 |
1 files changed, 137 insertions, 9 deletions
diff --git a/src/prop/prop_engine.h b/src/prop/prop_engine.h index 16cb34e04..25697b856 100644 --- a/src/prop/prop_engine.h +++ b/src/prop/prop_engine.h @@ -26,6 +26,9 @@ #include "expr/node.h" #include "util/options.h" #include "util/result.h" +#include "smt/modal_exception.h" + +#include <sys/time.h> namespace CVC4 { @@ -36,6 +39,80 @@ namespace prop { class CnfStream; class SatSolver; +class PropEngine; + +/** + * A helper class to keep track of a time budget and signal + * the PropEngine when the budget expires. + */ +class SatTimer { + + PropEngine& d_propEngine; + unsigned long d_ms; + timeval d_limit; + +public: + + /** Construct a SatTimer attached to the given PropEngine. */ + SatTimer(PropEngine& propEngine) : + d_propEngine(propEngine), + d_ms(0) { + } + + /** Is the timer currently active? */ + bool on() const { + return d_ms != 0; + } + + /** Set a millisecond timer (0==off). */ + void set(unsigned long millis) { + d_ms = millis; + // keep track of when it was set, even if it's disabled (i.e. == 0) + Trace("limit") << "SatTimer::set(" << d_ms << ")" << std::endl; + gettimeofday(&d_limit, NULL); + Trace("limit") << "SatTimer::set(): it's " << d_limit.tv_sec << "," << d_limit.tv_usec << std::endl; + d_limit.tv_sec += millis / 1000; + d_limit.tv_usec += (millis % 1000) * 1000; + if(d_limit.tv_usec > 1000000) { + ++d_limit.tv_sec; + d_limit.tv_usec -= 1000000; + } + Trace("limit") << "SatTimer::set(): limit is at " << d_limit.tv_sec << "," << d_limit.tv_usec << std::endl; + } + + /** Return the milliseconds elapsed since last set(). */ + unsigned long elapsed() { + timeval tv; + gettimeofday(&tv, NULL); + Trace("limit") << "SatTimer::elapsed(): it's now " << tv.tv_sec << "," << tv.tv_usec << std::endl; + tv.tv_sec -= d_limit.tv_sec - d_ms / 1000; + tv.tv_usec -= d_limit.tv_usec - (d_ms % 1000) * 1000; + Trace("limit") << "SatTimer::elapsed(): elapsed time is " << tv.tv_sec << "," << tv.tv_usec << std::endl; + return tv.tv_sec * 1000 + tv.tv_usec / 1000; + } + + bool expired() { + if(on()) { + timeval tv; + gettimeofday(&tv, NULL); + Trace("limit") << "SatTimer::expired(): current time is " << tv.tv_sec << "," << tv.tv_usec << std::endl; + Trace("limit") << "SatTimer::expired(): limit time is " << d_limit.tv_sec << "," << d_limit.tv_usec << std::endl; + if(d_limit.tv_sec < tv.tv_sec || + (d_limit.tv_sec == tv.tv_sec && d_limit.tv_usec <= tv.tv_usec)) { + Trace("limit") << "SatTimer::expired(): OVER LIMIT!" << std::endl; + return true; + } else { + Trace("limit") << "SatTimer::expired(): within limit" << std::endl; + } + } + return false; + } + + /** Check the current time and signal the PropEngine if over-time. */ + void check(); + +};/* class SatTimer */ + /** * PropEngine is the abstraction of a Sat Solver, providing methods for * solving the SAT problem and conversion to CNF (via the CnfStream). @@ -43,7 +120,7 @@ class SatSolver; class PropEngine { /** - * Indicates that the sat solver is currently solving something and we should + * Indicates that the SAT solver is currently solving something and we should * not mess with it's internal state. */ bool d_inCheckSat; @@ -51,6 +128,7 @@ class PropEngine { /** The theory engine we will be using */ TheoryEngine *d_theoryEngine; + /** The context */ context::Context* d_context; /** The SAT solver proxy */ @@ -62,6 +140,13 @@ class PropEngine { /** The CNF converter in use */ CnfStream* d_cnfStream; + /** A timer for SAT calls */ + SatTimer d_satTimer; + + /** Whether we were just interrupted (or not) */ + bool d_interrupted; + + /** Dump out the satisfying assignment (after SAT result) */ void printSatisfyingAssignment(); public: @@ -86,27 +171,34 @@ public: void shutdown() { } /** - * Converts the given formula to CNF and assert the CNF to the sat solver. + * Converts the given formula to CNF and assert the CNF to the SAT solver. * The formula is asserted permanently for the current context. * @param node the formula to assert */ void assertFormula(TNode node); /** - * Converts the given formula to CNF and assert the CNF to the sat solver. - * The formula can be removed by the sat solver after backtracking lower + * Converts the given formula to CNF and assert the CNF to the SAT solver. + * The formula can be removed by the SAT solver after backtracking lower * than the (SAT and SMT) level at which it was asserted. * * @param node the formula to assert - * @param negated whether the node should be considered to be negated at the top level (or not) - * @param removable whether this lemma can be quietly removed based on an activity heuristic (or not) + * @param negated whether the node should be considered to be negated + * at the top level (or not) + * @param removable whether this lemma can be quietly removed based + * on an activity heuristic (or not) */ void assertLemma(TNode node, bool negated, bool removable); /** * Checks the current context for satisfiability. + * + * @param millis the time limit for this call in milliseconds + * (0==off); on output, it is set to the milliseconds used + * @param on input, resource the number of resource units permitted + * for this call (0==off); on output, it is set to the resource used */ - Result checkSat(); + Result checkSat(unsigned long& millis, unsigned long& resource); /** * Get the value of a boolean variable. @@ -116,12 +208,19 @@ public: */ Node getValue(TNode node); - /* - * Return true if node has an associated SAT literal + /** + * Return true if node has an associated SAT literal. */ bool isSatLiteral(TNode node); /** + * Return true if node has an associated SAT literal that is + * currently translated (i.e., it's relevant to the current + * user push/pop level). + */ + bool isTranslatedSatLiteral(TNode node); + + /** * Check if the node has a value and return it if yes. */ bool hasValue(TNode node, bool& value); @@ -143,8 +242,37 @@ public: */ void pop(); + /** + * Check the current time budget. + */ + void checkTime(); + + /** + * Interrupt a running solver (cause a timeout). + */ + void interrupt() throw(ModalException); + + /** + * "Spend" a "resource." If the sum of these externally-counted + * resources and SAT-internal resources exceed the current limit, + * SAT should terminate. + */ + void spendResource() throw(); + };/* class PropEngine */ + +inline void SatTimer::check() { + if(expired()) { + Trace("limit") << "SatTimer::check(): interrupt!" << std::endl; + d_propEngine.interrupt(); + } +} + +inline void PropEngine::checkTime() { + d_satTimer.check(); +} + }/* CVC4::prop namespace */ }/* CVC4 namespace */ |