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relax.hh
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3 * Main authors:
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7 * Christian Schulte, 2016
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33
34#ifndef __GECODE_SEARCH_RELAX_HH__
35#define __GECODE_SEARCH_RELAX_HH__
36
37#include <gecode/kernel.hh>
38#include <gecode/search.hh>
39
40namespace Gecode { namespace Search {
41
43 template<class VarArgs, class Post>
44 forceinline void
45 relax(Home home, const VarArgs& x, const VarArgs& sx, Rnd r,
46 double p, Post& post);
47
48
49 template<class VarArgs, class Post>
50 forceinline void
51 relax(Home home, const VarArgs& x, const VarArgs& sx, Rnd r,
52 double p, Post& post) {
53 if (home.failed())
54 return;
55 Region reg;
56 // Which variables to assign
57 Support::BitSet<Region> ax(reg, static_cast<unsigned int>(x.size()));
58 // Select randomly with probability p to relax value
59 for (int i=0; i<x.size(); i++)
60 if (r(UINT_MAX) >=
61 static_cast<unsigned int>(p * static_cast<double>(UINT_MAX)))
62 ax.set(static_cast<unsigned int>(i));
63 if (ax.all())
64 // Choose one variable uniformly and unset it
65 ax.clear(r(static_cast<unsigned int>(x.size())));
66 for (Iter::Values::BitSet<Support::BitSet<Region> > i(ax); i(); ++i)
67 if (post(home, x[i.val()], sx[i.val()]) != ES_OK) {
68 home.failed();
69 return;
70 }
71 }
72
73}}
74
75#endif
76
77// STATISTICS: search-other
Home class for posting propagators
Definition core.hpp:856
bool failed(void) const
Check whether corresponding space is failed.
Definition core.hpp:4055
Value iterator for values in a bitset.
Handle to region.
Definition region.hpp:55
Random number generator.
Definition rnd.hpp:42
bool all(void) const
Test whether all bits are set.
void clear(unsigned int i)
Clear bit i.
void set(unsigned int i)
Set bit i.
Simple bitsets.
Definition bitset.hpp:45
Search engines
void relax(Home home, const VarArgs &x, const VarArgs &sx, Rnd r, double p, Post &post)
Relax variables in x from solution sx with probability p.
Definition relax.hh:51
Gecode toplevel namespace
Post propagator for SetVar SetOpType SetVar SetRelType r
Definition set.hh:773
TFE post(PropagatorGroup g)
Only post functions (but not propagators) from g are considered.
Definition filter.cpp:138
@ ES_OK
Execution is okay.
Definition core.hpp:476
Post propagator for SetVar x
Definition set.hh:773
#define forceinline
Definition config.hpp:194