src/ell/StateAcceptor.cc

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00001 #include "ell/StateAcceptor.hh"
00002 #include "biu/RandomNumberFactory.hh" // for SA_Metropolis
00003 #include <math.h> // exp for SA_Metropolis
00004 
00005 
00006 using namespace ell;
00007 
00008 bool
00009 SA_All::accept(const StateCollector* const sc, const State& succ) const
00010 {
00011     return true;
00012 }
00013 
00014 bool
00015 SA_E_Eq::accept(const StateCollector* const sc, const State& succ) const
00016 {
00017     if ( succ.getEnergy() == sc->getLastAdded()->getEnergy())
00018         return true;
00019     else
00020         return false;
00021 }
00022 
00023 bool
00024 SA_E_Gr::accept(const StateCollector* const sc, const State& succ) const
00025 {
00026     if ( succ.getEnergy() > sc->getLastAdded()->getEnergy())
00027         return true;
00028     else
00029         return false;
00030 }
00031 
00032 bool
00033 SA_E_GrEq::accept(const StateCollector* const sc, const State& succ) const
00034 {
00035     if ( succ.getEnergy() >= sc->getLastAdded()->getEnergy())
00036         return true;
00037     else
00038         return false;
00039 }
00040 
00041 bool
00042 SA_E_Le::accept(const StateCollector* const sc, const State& succ) const
00043 {
00044     if ( succ.getEnergy() < sc->getLastAdded()->getEnergy())
00045         return true;
00046     else
00047         return false;
00048 }
00049 
00050 bool
00051 SA_E_LeEq::accept(const StateCollector* const sc, const State& succ) const
00052 {
00053     if ( succ.getEnergy() <= sc->getLastAdded()->getEnergy())
00054         return true;
00055     else
00056         return false;
00057 }
00058 
00059 bool
00060 SA_EC_Le::accept(const StateCollector* const sc, const State& succ) const
00061 {
00062     if ( succ.getEnergy() < sc->getLastAdded()->getEnergy()) {
00063         return true;
00064     } else if ( succ.getEnergy() == sc->getLastAdded()->getEnergy()
00065                 && succ.compress() < sc->getLastAdded()->compress() ) 
00066     {
00067         return true;
00068     } else {
00069         return false;
00070     }
00071 }
00072 
00073 SA_Metropolis::SA_Metropolis(const double _beta) :beta(_beta) {}
00074 
00075 bool
00076 SA_Metropolis::accept(const StateCollector* const sc, const State& succ) const
00077 {   
00078     // compute energy difference
00079     double deltaE = succ.getEnergy() - sc->getLastAdded()->getEnergy();
00080     // compute probability for accepting state -> Metropolis
00081     double p = exp((-1)*beta*deltaE);
00082     
00083     // compute random number 0 <= r <= 1
00084     double r = (((double) biu::RNF::getRN()) / ((double) biu::RNF::getMaxRN())); 
00085 
00086     // return true with probability p
00087     if (p>r) return true;
00088     else return false;
00089 }