LIST list_CopyWithElement(const LIST List, POINTER (*CopyElement)(POINTER))
/**************************************************************
INPUT: A List and a copy function for the elements.
RETURNS: The copy of the list.
CAUTION: The entries of the list are NOT copied !
The function needs time O(n*c), where <n> is the length
of the list and <c> is the time for a call of the
element copy function.
***************************************************************/
{
LIST Copy;
LIST Scan1,Scan2;
if (list_Empty(List))
return list_Nil();
Copy = list_List(CopyElement(list_Car(List)));
Scan1 = Copy;
Scan2 = list_Cdr(List);
while (!list_Empty(Scan2)) {
list_Rplacd(Scan1, list_List(CopyElement(list_Car(Scan2))));
Scan1 = list_Cdr(Scan1);
Scan2 = list_Cdr(Scan2);
}
return Copy;
}
LIST list_Copy(const LIST List)
/**************************************************************
INPUT: A List.
RETURNS: The copy of the list.
CAUTION: The entries of the list are NOT copied !
the function needs time O(n), where <n> is the length
of the list.
***************************************************************/
{
LIST Copy;
LIST Scan1,Scan2;
if (list_Empty(List))
return list_Nil();
Copy = list_List(list_Car(List));
Scan1 = Copy;
Scan2 = list_Cdr(List);
while (!list_Empty(Scan2)) {
list_Rplacd(Scan1, list_List(list_Car(Scan2)));
Scan1 = list_Cdr(Scan1);
Scan2 = list_Cdr(Scan2);
}
return Copy;
}
static CLAUSE inf_CreateURUnitResolvent(CLAUSE Clause, int i, SUBST Subst,
LIST FoundMap, FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A non-unit clause, a literal index from the clause,
a substitution, a list of pairs (l1, l2) of literals,
where l1 is from the non-unit clause and l2 is from a
unit clause, a flag store and a precedence.
RETURNS: The resolvent of this UR resolution inference. The
clause consists of the literal at index <i> in <Clause>
after application of <Subst>.
EFFECT: The flag store and the precedence are needed to create
the new clause.
***************************************************************/
{
CLAUSE Result, PClause;
LITERAL Lit;
TERM Atom;
LIST Parents;
NAT depth;
/* Create atom for resolvent */
Atom = subst_Apply(Subst, term_Copy(clause_GetLiteralAtom(Clause, i)));
/* Create clause */
Parents = list_List(Atom);
if (i <= clause_LastConstraintLitIndex(Clause))
Result = clause_Create(Parents, list_Nil(), list_Nil(), Flags, Precedence);
else if (i <= clause_LastAntecedentLitIndex(Clause))
Result = clause_Create(list_Nil(), Parents, list_Nil(), Flags, Precedence);
else
Result = clause_Create(list_Nil(), list_Nil(), Parents, Flags, Precedence);
list_Delete(Parents);
/* Get parent clauses and literals, calculate depth of resolvent */
Parents = list_List(Clause);
depth = clause_Depth(Clause);
for ( ; !list_Empty(FoundMap); FoundMap = list_Cdr(FoundMap)) {
Lit = list_PairSecond(list_Car(FoundMap)); /* Literal from unit */
PClause = clause_LiteralOwningClause(Lit);
Parents = list_Cons(PClause, Parents);
depth = misc_Max(depth, clause_Depth(PClause));
clause_AddParentClause(Result, clause_Number(PClause));
clause_AddParentLiteral(Result, clause_LiteralGetIndex(Lit));
Lit = list_PairFirst(list_Car(FoundMap)); /* Is from <Clause> */
clause_AddParentClause(Result, clause_Number(Clause));
clause_AddParentLiteral(Result, clause_LiteralGetIndex(Lit));
}
clause_SetFromURResolution(Result);
clause_SetDepth(Result, depth+1);
clause_SetSplitDataFromList(Result, Parents);
list_Delete(Parents);
return Result;
}
static void st_NodeAddInner(st_INDEX StIndex, SUBST SubstOld, SUBST SubstNew,
SUBST ComGen, st_MINMAX MinMax, POINTER Pointer)
/**************************************************************
INPUT:
RETURNS:
EFFECTS:
***************************************************************/
{
st_INDEX OldIndexNode;
OldIndexNode = st_Get();
OldIndexNode->subst = SubstOld;
OldIndexNode->entries = StIndex->entries;
OldIndexNode->subnodes = StIndex->subnodes;
st_SetMax(OldIndexNode, st_Max(StIndex));
st_SetMin(OldIndexNode, st_Min(StIndex));
subst_Delete(StIndex->subst);
StIndex->subst = ComGen;
StIndex->entries = list_Nil();
StIndex->subnodes = list_Cons(st_NodeAddLeaf(SubstNew, MinMax, Pointer),
list_List(OldIndexNode));
if (st_Max(StIndex) < MinMax)
st_SetMax(StIndex, MinMax);
else if (st_Min(StIndex) > MinMax)
st_SetMin(StIndex, MinMax);
}
CLAUSE red_Terminator(CLAUSE RedClause, NAT n, SHARED_INDEX WoIndex,
SHARED_INDEX UsIndex, FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause, two shared indexes, a number <n>
restricting the number of non-unit clauses in
a possible terminator situation, a flag store
and a precedence.
RETURNS: An empty clause if a terminator with at most <n>
non-unit clauses is found, NULL otherwise.
EFFECT: See also description of red_SearchTerminator.
***************************************************************/
{
LIST Rest, IndexList;
CLAUSE Result;
if (clause_Length(RedClause) > 1) /* non-unit clause */
n--;
/* Pass the indexes as a list to sub-functions */
IndexList = list_Cons(WoIndex, list_List(UsIndex));
Rest = clause_GetLiteralList(RedClause);
Result = red_SearchTerminator(n, Rest, list_Nil(), subst_Nil(),
clause_MaxVar(RedClause), IndexList, Flags,
Precedence);
/* cleanup */
list_Delete(IndexList);
list_Delete(Rest);
return Result;
}
static st_INDEX st_NodeAddLeaf(SUBST Subst, st_MINMAX MinMax, POINTER Pointer)
/**************************************************************
INPUT:
RETURNS:
EFFECTS:
***************************************************************/
{
st_INDEX NewLeaf;
NewLeaf = st_Get();
NewLeaf->subnodes = list_Nil();
NewLeaf->entries = list_List(Pointer);
NewLeaf->subst = Subst;
st_SetMax(NewLeaf, MinMax);
st_SetMin(NewLeaf, MinMax);
return NewLeaf;
}
LIST inf_URResolution(CLAUSE Clause, SHARED_INDEX Index, FLAGSTORE Flags,
PRECEDENCE Precedence)
/**************************************************************
INPUT: A clause, a shared index, a flag store and a precedence.
RETURNS: The list of UR resolution resolvents.
EFFECT: The flag store and the precedence are needed to create
the resolvents.
***************************************************************/
{
LIST Result;
if (clause_Length(Clause) != 1) {
/* Clause isn't unit clause */
Result = inf_NonUnitURResolution(Clause, -1, list_Nil(), subst_Nil(),
clause_MaxVar(Clause), Index, Flags,
Precedence);
}
else {
/* Clause is unit clause, so search partner literals in non-unit clauses */
LITERAL Lit, PLit;
TERM Atom;
LIST Partners, FoundMap;
SYMBOL MaxVar, PMaxVar;
SUBST LeftSubst, RightSubst;
CLAUSE PClause;
int PLitInd;
BOOL Swapped;
Result = list_Nil();
Lit = clause_GetLiteral(Clause, clause_FirstLitIndex());
Atom = term_Copy(clause_LiteralAtom(Lit));
Swapped = FALSE;
/* The following 'endless' loop runs twice for equality literals */
/* and only once for other literals. */
while (TRUE) {
/* Get complementary literals from non-unit clauses */
Partners = inf_GetURPartnerLits(Atom, Lit, FALSE, Index);
for ( ; !list_Empty(Partners); Partners = list_Pop(Partners)) {
PLit = list_Car(Partners);
PLitInd = clause_LiteralGetIndex(PLit);
PClause = clause_LiteralOwningClause(PLit); /* non-unit clause */
PMaxVar = clause_MaxVar(PClause);
term_StartMaxRenaming(PMaxVar);
term_Rename(Atom); /* Rename atom from unit clause */
MaxVar = term_MaxVar(Atom);
if (symbol_GreaterVariable(PMaxVar, MaxVar))
MaxVar = PMaxVar;
/* Get the substitution */
cont_Check();
unify_UnifyNoOC(cont_LeftContext(), clause_LiteralAtom(PLit),
cont_RightContext(), Atom);
subst_ExtractUnifier(cont_LeftContext(), &LeftSubst,
cont_RightContext(), &RightSubst);
cont_Reset();
/* We don't need the substitution for the unit clause */
subst_Delete(RightSubst);
FoundMap = list_List(list_PairCreate(PLit, Lit));
Result = list_Nconc(inf_NonUnitURResolution(PClause, PLitInd, FoundMap,
LeftSubst, MaxVar, Index,
Flags, Precedence),
Result);
list_DeletePairList(FoundMap);
subst_Delete(LeftSubst);
}
/* loop control */
if (!fol_IsEquality(Atom) || Swapped)
break;
else {
term_EqualitySwap(Atom);
Swapped = TRUE;
}
} /* end of endless loop */
term_Delete(Atom);
}
return Result;
}
static LIST inf_SearchURResolvents(CLAUSE Clause, int i, LIST FoundMap,
LIST RestLits, SUBST Subst,
SYMBOL GlobalMaxVar, SHARED_INDEX Index,
FLAGSTORE Flags, PRECEDENCE Precedence)
/**************************************************************
INPUT: A non-unit clause, a literal index from <Clause>.
<FoundMap> is a list of pairs (l1,l2) of unifiable literals,
where l1 is from <Clause> and l2 is from a unit clause.
<RestLits> is a list of literals from <Clause> where
we haven't found unifiable literals from unit clauses
so far.
<Subst> is the overall substitution for <Clause>
(not for the unit-clauses!).
<GlobalMaxVar> is the maximal variable encountered so far.
<Index> is used to search unifiable literals.
The flag store and the precedence are needed to create
the new clauses.
RETURNS: A list of UR resolution resolvents.
***************************************************************/
{
if (list_Empty(RestLits)) {
/* Stop the recursion */
return list_List(inf_CreateURUnitResolvent(Clause, i, Subst, FoundMap,
Flags, Precedence));
} else {
LITERAL Lit, PLit;
SYMBOL NewMaxVar;
SUBST NewSubst, RightSubst;
TERM AtomCopy, PAtom;
LIST Result, Partners;
BOOL Swapped;
Result = list_Nil();
Swapped = FALSE;
/* Choose the unmatched literal with the most symbols */
RestLits = clause_MoveBestLiteralToFront(list_Copy(RestLits), Subst,
GlobalMaxVar,
clause_HyperLiteralIsBetter);
Lit = list_Car(RestLits);
RestLits = list_Pop(RestLits);
AtomCopy = subst_Apply(Subst, term_Copy(clause_LiteralAtom(Lit)));
/* The following 'endless' loop runs twice for equality literals */
/* and only once for other literals. */
while (TRUE) {
Partners = inf_GetURPartnerLits(AtomCopy, Lit, TRUE, Index);
for ( ; !list_Empty(Partners); Partners = list_Pop(Partners)) {
PLit = list_Car(Partners);
/* Rename the atom */
PAtom = term_Copy(clause_LiteralAtom(PLit));
term_StartMaxRenaming(GlobalMaxVar);
term_Rename(PAtom);
/* Get the new global maximal variable */
NewMaxVar = term_MaxVar(PAtom);
if (symbol_GreaterVariable(GlobalMaxVar, NewMaxVar))
NewMaxVar = GlobalMaxVar;
/* Get the substitution */
cont_Check();
if (!unify_UnifyNoOC(cont_LeftContext(), AtomCopy,
cont_RightContext(), PAtom)) {
misc_StartErrorReport();
misc_ErrorReport("\n In inf_SearchURResolvents: Unification failed.");
misc_FinishErrorReport();
}
subst_ExtractUnifier(cont_LeftContext(), &NewSubst,
cont_RightContext(), &RightSubst);
cont_Reset();
subst_Delete(RightSubst); /* Forget substitution for unit clause */
term_Delete(PAtom); /* Was just needed to get the substitution */
/* Build the composition of the substitutions */
RightSubst = NewSubst;
NewSubst = subst_Compose(NewSubst, subst_Copy(Subst));
subst_Delete(RightSubst);
FoundMap = list_Cons(list_PairCreate(Lit, PLit), FoundMap);
Result = list_Nconc(inf_SearchURResolvents(Clause,i,FoundMap,RestLits,
NewSubst,NewMaxVar,Index,
Flags, Precedence),
Result);
list_PairFree(list_Car(FoundMap));
FoundMap = list_Pop(FoundMap);
subst_Delete(NewSubst);
}
/* loop control */
if (!fol_IsEquality(AtomCopy) || Swapped)
break;
else {
term_EqualitySwap(AtomCopy);
Swapped = TRUE;
}
}
/* cleanup */
term_Delete(AtomCopy);
list_Delete(RestLits);
return Result;
}
}
