def new_atoms(cycle: List[structures.Atom], q: structures.ConjunctiveQuery, rewriting_index: int,
renaming: Dict[structures.AtomValue, structures.AtomValue]) -> \
Tuple[Tuple[structures.Atom, structures.FunctionalDependencySet, List[bool], bool],
List[Tuple[structures.Atom, structures.FunctionalDependencySet, List[bool], bool]]]:
"""
Generates the atoms needed for the reduction
:param cycle: Cycle being reduced
:param q: A ConjunctiveQuery
:param rewriting_index: Index used to enumerate the Datalog rules
:param renaming: Necessary renaming
:return: Atoms needed for the reduction
"""
_, x_0, _ = q.decompose_atom(cycle[0])
x_0_ren = algorithms.apply_renaming_to_atom_values(x_0, renaming)
n_atoms = []
t_content = []
t_released = set()
for atom in cycle:
_, x, y = q.decompose_atom(atom)
n = structures.Atom("N_" + atom.name, x + x_0_ren, atom.released)
t_released = t_released.union(atom.released)
fd = structures.FunctionalDependencySet()
for var in x_0_ren:
fd.add(structures.FunctionalDependency(x, var))
is_key = [True] * len(x) + [False] * len(x_0_ren)
n_atoms.append((n, fd, is_key, True))
t_content += x
t_content += y
t = structures.Atom("T_" + str(rewriting_index), x_0_ren + t_content, t_released)
fd = structures.FunctionalDependencySet()
for var in t_content:
fd.add(structures.FunctionalDependency(x_0_ren, var))
is_key = [True] * len(x_0_ren) + [False] * len(t_content)
return (t, fd, is_key, False), n_atoms
def __init__(self, q: ConjunctiveQuery, atom: Atom, index: int,
is_last: bool, done: Set[Atom]):
self.q = q
self.atom = atom
self.index = index
self.v, self.x, self.y = q.decompose_atom(atom)
_, self.vars_x, self.vars_y = q.decompose_atom(atom, True)
self.vars_z, self.c = generate_z_and_c(self.x, self.y, self.vars_y,
index)
self.has_c = len(self.c) > 0
self.is_last = is_last
self.frozen = q.free_vars
self.new_frozen = []
for var in q.free_vars:
self.new_frozen.append(var)
for var in self.v:
if var not in self.new_frozen:
self.new_frozen.append(var)
self.done = done
def new_atoms_rules(cycle: List[structures.Atom], q: structures.ConjunctiveQuery, rewriting_index : int,
renamings: List[Dict[structures.AtomValue, structures.AtomValue]]) -> List[structures.DatalogQuery]:
"""
Generated the rules defining the new atoms added by the reduction
:param cycle: Cycle being reduced
:param q: A ConjunctiveQuery
:param rewriting_index: Index used to enumerate the Datalog rules
:param renamings: Necessary renamings
:return: Rules defining the new atoms
"""
_, x_0, _ = q.decompose_atom(cycle[0])
rules = []
rules += [templates.KeepQuery(atom, q) for atom in cycle]
rules += [templates.LinkQuery(atom, cycle, q, rewriting_index, renamings[0]) for atom in cycle]
rules += [templates.TransBaseQuery(cycle, q, rewriting_index, renamings[0])]
rules += [templates.TransRecQuery(cycle, q, rewriting_index, renamings)]
if len(x_0) > 1:
rules += [templates.LowerCompositeQuery(cycle, q, i, rewriting_index, renamings) for i in range(len(x_0))]
else:
rules += [templates.LowerSingleQuery(cycle, q, rewriting_index, renamings)]
rules += [templates.IdentifiedByQuery(cycle, q, rewriting_index, renamings[0])]
rules += [templates.NQuery(atom, cycle, q, rewriting_index, renamings[0]) for atom in cycle]
rules += [templates.TQuery(cycle, q, rewriting_index, renamings[0])]
return rules