void compile_vtree_shannon(NNF_NODE* node, Clause** learned_clause, DVtree* vtree, VtreeManager* vtree_manager, NnfManager* nnf_manager, SatState* sat_state) {
Var* var = vtree_shannon_var(vtree);
if(sat_instantiated_var(var) || sat_irrelevant_var(var)) {
compile_dispatcher(node,learned_clause,vtree->right,vtree_manager,nnf_manager,sat_state);
if(*learned_clause==NULL) *node = nnf_conjoin(*node,var2nnf(var,nnf_manager),nnf_manager);
return;
}
Lit* plit = sat_pos_literal(var);
Lit* nlit = sat_neg_literal(var);
if(!compile_with_literal(node,learned_clause,plit,vtree,vtree_manager,nnf_manager,sat_state)) return;
assert(*learned_clause==NULL);
assert(!sat_instantiated_var(var));
NNF_NODE pnode = *node; //save the node when conditioned on plit
if(!compile_with_literal(node,learned_clause,nlit,vtree,vtree_manager,nnf_manager,sat_state)) return;
assert(*learned_clause==NULL);
assert(!sat_instantiated_var(var));
NNF_NODE nnode = *node; //save the node when conditioned on nlit
if(pnode==nnode) *node = pnode;
else {
NNF_NODE pl = nnf_literal2node(plit,nnf_manager);
NNF_NODE nl = nnf_literal2node(nlit,nnf_manager);
NNF_NODE pc = nnf_conjoin(pl,pnode,nnf_manager);
NNF_NODE nc = nnf_conjoin(nl,nnode,nnf_manager);
*node = nnf_disjoin(var,pc,nc,nnf_manager);
}
}
NNF_NODE var2nnf(Var* var, NnfManager* nnf_manager) {
Lit* plit = sat_pos_literal(var);
Lit* nlit = sat_neg_literal(var);
if(sat_implied_literal(plit)) return nnf_literal2node(plit,nnf_manager);
else if(sat_implied_literal(nlit)) return nnf_literal2node(nlit,nnf_manager);
else return ONE_NNF_NODE;
}
Lit* sat_opp_literal(const Lit* lit) {
Var* var = sat_literal_var(lit);
return lit->index > 0 ? sat_neg_literal(var) : sat_pos_literal(var);
}
//returns 1 if the variable is instantiated, 0 otherwise
//a variable is instantiated either by decision or implication (by unit resolution)
BOOLEAN sat_instantiated_var(const Var* var) {
Lit* plit = sat_pos_literal(var);
Lit* nlit = sat_neg_literal(var);
return sat_implied_literal(plit) || sat_implied_literal(nlit);
}
/******************************************************************************
* Parse Clause line
* -- For each line in the DIMACS file construct a new clause struct
* -- initialize the array of literals this clause contains
******************************************************************************/
static unsigned long parseClause(SatState* sat_state, char* line, Clause* clause){
char* pch = NULL;
unsigned long countvariables = 0;
//Lit* literals = (Lit *) malloc(sizeof (Lit));
#ifdef DEBUG
printf("%s\n",line);
#endif
// initialize memory of clause literals with one element and then increase the size by double if needed
unsigned long MIN_CAPACITY = 1;
clause->literals = (Lit**) malloc(sizeof(Lit*) * MIN_CAPACITY);
//separate the string into space separated tokens
pch = strtok(line, " \t");
while (pch != NULL){
//#ifdef DEBUG
// printf("%s\n", pch);
//#endif
if(atol(pch) == END_OF_CLAUSE_LINE){
break;
}
if(countvariables >= MIN_CAPACITY){
// needs to realloc the size
MIN_CAPACITY = countvariables * MALLOC_GROWTH_RATE;
clause->literals = (Lit**) realloc( clause->literals, sizeof(Lit*) * MIN_CAPACITY);
}
signed long value = atol(pch);
Var* var = &(sat_state->variables[abs(value) - 1]); // because array is filled from 0 to n-1
if(value < 0)
clause->literals[countvariables] = sat_neg_literal(var);
else if (value > 0)
clause->literals[countvariables] = sat_pos_literal(var);
add_clause_to_variable(var, clause);
add_clause_to_variable_from_cnf(var, clause);
add_clause_to_literal(clause->literals[countvariables], clause);
//#ifdef DEBUG
// print_clause_containing_literal(clause->literals[countvariables]);
//#endif
countvariables ++;
pch = strtok (NULL, " \t");
}
clause->num_literals_in_clause = countvariables;
clause->max_size_list_literals = MIN_CAPACITY;
clause->is_subsumed = 0;
// For the two literal watch // just initialize here
if(clause->num_literals_in_clause > 1){
clause->L1 = clause->literals[0]; // first literal
add_watching_clause(clause, clause->L1);
clause->L2 = clause->literals[1]; // second literal
add_watching_clause(clause, clause->L2);
}
else{ //unit clause
clause->L1 = clause->literals[0];
add_watching_clause(clause, clause->L1);
clause->L2 = NULL;
}
clause->mark = 0; // THIS FIELD AS IT DESCRIBED BY IN THE REQUIREMENTS
return countvariables;
}
