def __search(sync_net, ini, fin, cost_function, skip, ret_tuple_as_trans_desc=False,
             max_align_time_trace=sys.maxsize):
    start_time = time.time()

    decorate_transitions_prepostset(sync_net)
    decorate_places_preset_trans(sync_net)

    incidence_matrix = inc_mat_construct(sync_net)
    ini_vec, fin_vec, cost_vec = utils.__vectorize_initial_final_cost(incidence_matrix, ini, fin, cost_function)

    closed = set()

    a_matrix = np.asmatrix(incidence_matrix.a_matrix).astype(np.float64)
    g_matrix = -np.eye(len(sync_net.transitions))
    h_cvx = np.matrix(np.zeros(len(sync_net.transitions))).transpose()
    cost_vec = [x * 1.0 for x in cost_vec]

    use_cvxopt = False
    if lp_solver.DEFAULT_LP_SOLVER_VARIANT == lp_solver.CVXOPT_SOLVER_CUSTOM_ALIGN or lp_solver.DEFAULT_LP_SOLVER_VARIANT == lp_solver.CVXOPT_SOLVER_CUSTOM_ALIGN_ILP:
        use_cvxopt = True

    if use_cvxopt:
        # not available in the latest version of PM4Py
        from cvxopt import matrix

        a_matrix = matrix(a_matrix)
        g_matrix = matrix(g_matrix)
        h_cvx = matrix(h_cvx)
        cost_vec = matrix(cost_vec)

    h, x = utils.__compute_exact_heuristic_new_version(sync_net, a_matrix, h_cvx, g_matrix, cost_vec, incidence_matrix,
                                                       ini,
                                                       fin_vec, lp_solver.DEFAULT_LP_SOLVER_VARIANT,
                                                       use_cvxopt=use_cvxopt)
    ini_state = utils.SearchTuple(0 + h, 0, h, ini, None, None, x, True)
    open_set = [ini_state]
    heapq.heapify(open_set)
    visited = 0
    queued = 0
    traversed = 0
    lp_solved = 1

    trans_empty_preset = set(t for t in sync_net.transitions if len(t.in_arcs) == 0)

    while not len(open_set) == 0:
        if (time.time() - start_time) > max_align_time_trace:
            return None

        curr = heapq.heappop(open_set)

        current_marking = curr.m

        while not curr.trust:
            if (time.time() - start_time) > max_align_time_trace:
                return None

            already_closed = current_marking in closed
            if already_closed:
                curr = heapq.heappop(open_set)
                current_marking = curr.m
                continue

            h, x = utils.__compute_exact_heuristic_new_version(sync_net, a_matrix, h_cvx, g_matrix, cost_vec,
                                                               incidence_matrix, curr.m,
                                                               fin_vec, lp_solver.DEFAULT_LP_SOLVER_VARIANT,
                                                               use_cvxopt=use_cvxopt)
            lp_solved += 1

            # 11/10/19: shall not a state for which we compute the exact heuristics be
            # by nature a trusted solution?
            tp = utils.SearchTuple(curr.g + h, curr.g, h, curr.m, curr.p, curr.t, x, True)
            # 11/10/2019 (optimization ZA) heappushpop is slightly more efficient than pushing
            # and popping separately
            curr = heapq.heappushpop(open_set, tp)
            current_marking = curr.m

        # max allowed heuristics value (27/10/2019, due to the numerical instability of some of our solvers)
        if curr.h > lp_solver.MAX_ALLOWED_HEURISTICS:
            continue

        # 12/10/2019: do it again, since the marking could be changed
        already_closed = current_marking in closed
        if already_closed:
            continue

        # 12/10/2019: the current marking can be equal to the final marking only if the heuristics
        # (underestimation of the remaining cost) is 0. Low-hanging fruits
        if curr.h < 0.01:
            if current_marking == fin:
                return utils.__reconstruct_alignment(curr, visited, queued, traversed,
                                                     ret_tuple_as_trans_desc=ret_tuple_as_trans_desc,
                                                     lp_solved=lp_solved)

        closed.add(current_marking)
        visited += 1

        enabled_trans = copy(trans_empty_preset)
        for p in current_marking:
            for t in p.ass_trans:
                if t.sub_marking <= current_marking:
                    enabled_trans.add(t)

        trans_to_visit_with_cost = [(t, cost_function[t]) for t in enabled_trans if not (
                t is not None and utils.__is_log_move(t, skip) and utils.__is_model_move(t, skip))]

        for t, cost in trans_to_visit_with_cost:
            traversed += 1
            new_marking = utils.add_markings(current_marking, t.add_marking)

            if new_marking in closed:
                continue
            g = curr.g + cost

            queued += 1
            h, x = utils.__derive_heuristic(incidence_matrix, cost_vec, curr.x, t, curr.h)
            trustable = utils.__trust_solution(x)
            new_f = g + h

            tp = utils.SearchTuple(new_f, g, h, new_marking, curr, t, x, trustable)
            heapq.heappush(open_set, tp)
Beispiel #2
0
def __search(sync_net, ini, fin, stop, cost_function, skip):
    decorate_transitions_prepostset(sync_net)
    decorate_places_preset_trans(sync_net)

    incidence_matrix = construct(sync_net)
    ini_vec, fin_vec, cost_vec = utils.__vectorize_initial_final_cost(
        incidence_matrix, ini, fin, cost_function)

    closed = set()

    ini_state = utils.SearchTuple(0, 0, 0, ini, None, None, None, True)
    open_set = [ini_state]
    heapq.heapify(open_set)
    visited = 0
    queued = 0
    traversed = 0

    # return all the prefix markings of the optimal alignments as set
    ret_markings = None
    # keep track of the optimal cost of an alignment (to trim search when needed)
    optimal_cost = None

    while not len(open_set) == 0:
        curr = heapq.heappop(open_set)

        current_marking = curr.m

        # trim alignments when we already reached an optimal alignment and the
        # current cost is greater than the optimal cost
        if optimal_cost is not None and curr.f > optimal_cost:
            break

        already_closed = current_marking in closed
        if already_closed:
            continue

        if stop <= current_marking:
            # add the current marking to the set
            # of returned markings
            if ret_markings is None:
                ret_markings = set()
            ret_markings.add(current_marking)
            # close the marking
            closed.add(current_marking)
            # set the optimal cost
            optimal_cost = curr.f

            continue

        closed.add(current_marking)
        visited += 1

        enabled_trans = set()
        for p in current_marking:
            for t in p.ass_trans:
                if t.sub_marking <= current_marking:
                    enabled_trans.add(t)

        trans_to_visit_with_cost = [
            (t, cost_function[t]) for t in enabled_trans
            if not (t is None or utils.__is_log_move(t, skip) or (
                utils.__is_model_move(t, skip) and not t.label[1] is None))
        ]

        for t, cost in trans_to_visit_with_cost:
            traversed += 1
            new_marking = utils.add_markings(current_marking, t.add_marking)

            if new_marking in closed:
                continue
            g = curr.g + cost

            queued += 1
            new_f = g

            tp = utils.SearchTuple(new_f, g, 0, new_marking, curr, t, None,
                                   True)
            heapq.heappush(open_set, tp)

    return ret_markings
Beispiel #3
0
    def search(self):
        incidence_matrix = self.incidence_matrix
        ini_vec, fin_vec, cost_vec = self.__vectorize_initial_final_cost(
            self.incidence_matrix, self.ini, self.fin, self.cost_function)
        closed = set()
        cost_vec = [x * 1.0 for x in cost_vec]
        start_time = timeit.default_timer()
        h, x = compute_init_heuristic_without_split(
            np.array(np.array(fin_vec) - np.array(ini_vec)),
            np.array(incidence_matrix.a_matrix), np.array(cost_vec))
        self.heuristic_time += timeit.default_timer() - start_time
        ini_state = utils.SearchTuple(0 + h, 0, h, self.ini, None, None, x,
                                      True)
        open_set = [ini_state]
        self.num_insert += 1
        heapq.heapify(open_set)
        self.queue_time += timeit.default_timer() - start_time
        self.simple_lp = 1
        trans_empty_preset = set(t for t in incidence_matrix.transitions
                                 if len(t.in_arcs) == 0)
        while not len(open_set) == 0:
            start_time = timeit.default_timer()
            curr = heapq.heappop(open_set)
            self.queue_time += timeit.default_timer() - start_time
            self.num_removal += 1
            current_marking = curr.m
            while not curr.trust:
                already_closed = current_marking in closed
                if already_closed:
                    start_time = timeit.default_timer()
                    curr = heapq.heappop(open_set)
                    self.queue_time += timeit.default_timer() - start_time
                    self.num_removal += 1
                    current_marking = curr.m
                    continue
                start_time = timeit.default_timer()
                h, x = compute_init_heuristic_without_split(
                    np.array(fin_vec) -
                    np.array(incidence_matrix.encode_marking(curr.m)),
                    np.array(incidence_matrix.a_matrix), np.array(cost_vec))
                self.heuristic_time += timeit.default_timer() - start_time
                self.simple_lp += 1
                tp = utils.SearchTuple(curr.g + h, curr.g, h, curr.m, curr.p,
                                       curr.t, x, True)
                start_time = timeit.default_timer()
                curr = heapq.heappushpop(open_set, tp)
                self.queue_time += timeit.default_timer() - start_time
                self.num_insert += 1
                self.num_removal += 1
                current_marking = curr.m
            already_closed = current_marking in closed
            if already_closed:
                continue

            if curr.h < 0.01:
                if current_marking == self.fin:
                    return self._reconstruct_alignment(curr)

            closed.add(current_marking)
            self.visited += 1

            enabled_trans = copy(trans_empty_preset)
            for p in current_marking:
                for t in p.ass_trans:
                    if t.sub_marking <= current_marking:
                        enabled_trans.add(t)

            trans_to_visit_with_cost = [
                (t, self.cost_function[t]) for t in enabled_trans
                if not (t is not None and is_log_move(t, '>>')
                        and is_model_move(t, '>>'))
            ]

            for t, cost in trans_to_visit_with_cost:
                self.traversed += 1
                new_marking = utils.add_markings(current_marking,
                                                 t.add_marking)
                if new_marking in closed:
                    continue
                g = curr.g + cost
                h, x, trustable = derive_heuristic(
                    cost_vec, curr.x, incidence_matrix.transitions[t], curr.h)
                new_f = g + h
                tp = utils.SearchTuple(new_f, g, h, new_marking, curr, t, x,
                                       trustable)

                start_time = timeit.default_timer()
                heapq.heappush(open_set, tp)
                self.queue_time += timeit.default_timer() - start_time
                self.num_insert += 1