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ezSAT: Fixed handling of eliminated Literals, added auto-freeze for expressions

This commit is contained in:
Clifford Wolf 2014-03-03 02:12:45 +01:00
parent d500bd749f
commit 895e9fc70c
2 changed files with 23 additions and 8 deletions
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29
libs/ezsat/ezsat.cc
View File

@ -485,12 +485,16 @@ std::string ezSAT::cnfLiteralInfo(int idx) const
return "<unnamed>"; return "<unnamed>";
} }
int ezSAT::bind(int id) int ezSAT::bind(int id, bool auto_freeze)
{ {
if (id >= 0) { if (id >= 0) {
assert(0 < id && id <= int(literals.size())); assert(0 < id && id <= int(literals.size()));
cnfLiteralVariables.resize(literals.size()); cnfLiteralVariables.resize(literals.size());
if (cnfLiteralVariables[id-1] == 0 || eliminated(cnfLiteralVariables[id-1])) { if (eliminated(cnfLiteralVariables[id-1])) {
fprintf(stderr, "ezSAT: Missing freeze on literal `%s'.\n", to_string(id).c_str());
abort();
}
if (cnfLiteralVariables[id-1] == 0) {
cnfLiteralVariables[id-1] = ++cnfVariableCount; cnfLiteralVariables[id-1] = ++cnfVariableCount;
if (id == TRUE) if (id == TRUE)
add_clause(+cnfLiteralVariables[id-1]); add_clause(+cnfLiteralVariables[id-1]);
@ -503,7 +507,18 @@ int ezSAT::bind(int id)
assert(0 < -id && -id <= int(expressions.size())); assert(0 < -id && -id <= int(expressions.size()));
cnfExpressionVariables.resize(expressions.size()); cnfExpressionVariables.resize(expressions.size());
if (cnfExpressionVariables[-id-1] == 0 || eliminated(cnfExpressionVariables[-id-1])) if (eliminated(cnfExpressionVariables[-id-1]))
{
cnfExpressionVariables[-id-1] = 0;
// this will recursively call bind(id). within the recursion
// the cnf is pre-set to 0. an idx is allocated there, then it
// is frozen, then it returns here with the new idx already set.
if (auto_freeze)
freeze(id);
}
if (cnfExpressionVariables[-id-1] == 0)
{ {
OpId op; OpId op;
std::vector<int> args; std::vector<int> args;
@ -520,7 +535,7 @@ int ezSAT::bind(int id)
newArgs.push_back(OR(AND(args[i], NOT(args[i+1])), AND(NOT(args[i]), args[i+1]))); newArgs.push_back(OR(AND(args[i], NOT(args[i+1])), AND(NOT(args[i]), args[i+1])));
args.swap(newArgs); args.swap(newArgs);
} }
idx = bind(args.at(0)); idx = bind(args.at(0), false);
goto assign_idx; goto assign_idx;
} }
@ -528,17 +543,17 @@ int ezSAT::bind(int id)
std::vector<int> invArgs; std::vector<int> invArgs;
for (auto arg : args) for (auto arg : args)
invArgs.push_back(NOT(arg)); invArgs.push_back(NOT(arg));
idx = bind(OR(expression(OpAnd, args), expression(OpAnd, invArgs))); idx = bind(OR(expression(OpAnd, args), expression(OpAnd, invArgs)), false);
goto assign_idx; goto assign_idx;
} }
if (op == OpITE) { if (op == OpITE) {
idx = bind(OR(AND(args[0], args[1]), AND(NOT(args[0]), args[2]))); idx = bind(OR(AND(args[0], args[1]), AND(NOT(args[0]), args[2])), false);
goto assign_idx; goto assign_idx;
} }
for (int i = 0; i < int(args.size()); i++) for (int i = 0; i < int(args.size()); i++)
args[i] = bind(args[i]); args[i] = bind(args[i], false);
switch (op) switch (op)
{ {

2
libs/ezsat/ezsat.h
View File

@ -143,7 +143,7 @@ public:
virtual void freeze(int id); virtual void freeze(int id);
virtual bool eliminated(int idx); virtual bool eliminated(int idx);
void assume(int id); void assume(int id);
int bind(int id); int bind(int id, bool auto_freeze = true);
int bound(int id) const; int bound(int id) const;
int numCnfVariables() const { return cnfVariableCount; } int numCnfVariables() const { return cnfVariableCount; }