コード例 #1
0
def save_moves(sequence, s1, s2, dataset, indirect_moves, description):

    output_file = "./sample_seqs/indirect_db.csv"
    direct_search_width=1000

    print ("saving:")

    direct_result = pathfinder.pathfinder(sequence, s1, s2, search_width=direct_search_width)
    direct_moves = [(i[0], i[1]) for i in direct_result.paths[0]]

    print ("direct path:")
    en_direct = print_moves(sequence, s1, s2, direct_moves)
    print ("indirect path:")
    en_indirect = print_moves(sequence, s1, s2, indirect_moves)

    # en_direct = print_moves(sequence, s1, s2, direct_moves)
    # en_indirect = print_moves(sequence, s1, s2, indirect_moves)

    # columns = ["sequence","s1","s2", "en_direct", "en_indirect", "direct_moves","indirect_moves","description"]
    # df = pd.DataFrame(columns=columns)
    # df.loc[0] = [sequence,s1,s2,en_direct, en_indirect, direct_moves,indirect_moves,description]

    # only save if indirect en is lower than direct en
    if en_indirect < en_direct:           
        rna_db = RNA_db(dbname='./sample_db/rna_samples.sqlite')  
        rna_db.insert_path(sequence, s1, s2, dataset, indirect_moves, description)
コード例 #2
0
def save_moves(sequence, s1, s2, dataset, indirect_moves, description):

    direct_search_width = 1000

    direct_result = pathfinder.pathfinder(sequence,
                                          s1,
                                          s2,
                                          search_width=direct_search_width)
    direct_moves = [(i[0], i[1]) for i in direct_result.paths[0]]

    print("direct path:")
    en_direct = print_moves(sequence, s1, s2, direct_moves)
    print("indirect path:")
    en_indirect = print_moves(sequence, s1, s2, indirect_moves)

    # only save if indirect en is lower than direct en
    if en_indirect < en_direct:
        rna_db = RNA_db(dbname='./sample_db/rna_samples.sqlite')
        rna_db.insert_path(sequence, s1, s2, dataset, indirect_moves,
                           description)
コード例 #3
0
def pathfinder(sequence, s1, s2, verbose=False, output=False, search_width = None, section = None):

    # prune off sections which will currently not be regarded / later merged
    if section:
        if len(section)==2:
            start = section[0]
            end = section[1]
            s1 = '.'*start + s1[start:end] + '.'*(len(s1)-end)
            s2 = '.'*start + s2[start:end] + '.'*(len(s1)-end)
        if len(section)==4:
            # print ('section 4', section)
            start = section[0]
            mid1 = section[1]
            mid2 = section[2]
            end = section[3]
            s1 = '.'*start + s1[start:mid1] + '.'*(mid2-mid1) + s1[mid2:end] + '.'*(len(s1)-end)
            s2 = '.'*start + s2[start:mid1] + '.'*(mid2-mid1) + s2[mid2:end] + '.'*(len(s1)-end)
            # print (s1)
            # print (s2)



    start = time.time()
    # Set model details (by Stefan)
    md = RNA.md()
    md.temperature = 37.0
    # md.temperature = 22.0
    # How to treat "dangling end" energies for bases adjacent to helices in free ends and multi-loops.
    # md.dangles = 0
    md.dangles = 2
    md.logML = 0
    md.special_hp = True
    md.noGU = False
    md.noGUclosure = False
    fc = RNA.fold_compound(sequence, md)
    # fc = RNA.fold_compound(sequence)


    bpd = RNA.bp_distance(s1, s2)

    if verbose:
        print(f"Base-pair distance: {bpd}")


    max_energy = None  # Specify upper bound for barrier energy (kcal/mol).
    
    # search_width = None  # Adjust upper bound for findpath search.

    if search_width is None:
        search_width = 2 * bpd

    paths = fc.path_findpath(s1, s2, width=search_width)

    sE = float('-inf')     # saddle energy
    s_pos = 0
    en_min = float('inf')  # minimum, assuming we get below E1


    current_structure = ""

    # compare changes to previous move

    def str_compare(s1, s2):
        for i, (c1, c2) in enumerate(zip(s1, s2)):
            if c1 != c2:
                if c1 == ".":
                    yield i
                else:
                    yield -i

    moves_str = []
    moves_en = []
    moves_pos = []

    for i, step in enumerate(paths):
        moves = [i for i in str_compare('.'+current_structure, '.'+step.s)]

        current_structure = step.s
        moves_str.append(step.s)
        moves_en.append(step.en)

        if moves==[]:
            moves_pos.append((0,0,step.en))
        else:
            moves_pos.append((moves[0],moves[1],step.en))

        if step.en > sE:
            sE = step.en
            s_pos = i


    e1 = round(fc.eval_structure(s1), 2)
    e2 = round(fc.eval_structure(s2), 2)
    barrier = sE - e1

    # minimum between e1 and saddle energy (max energy)
    if len(moves_en[0:s_pos])==0:
        en_min_a = e1
    else:
        en_min_a = min(moves_en[0:s_pos])

    if len(moves_en[s_pos+1:])<=1:
        en_min_b = e2
    else:
        en_min_b = min(moves_en[s_pos+1:])

        # en_min_a = en_min-e1


    end = time.time()
    runtime = end - start


    if verbose:
        print_moves(sequence, s1, s2, moves_pos, move_color='\033[92m')


    return_path = path_class()
    return_path.max_en=sE
    return_path.max_en_pos=s_pos
    return_path.min_en_a=en_min_a
    return_path.min_en_b=en_min_b
    return_path.e1_en=e1
    return_path.e2_en=e2
    return_path.paths = [moves_pos]
    return_path.runtime = runtime

    return return_path
コード例 #4
0
def find_path(sequence, start_list, destination_list, max_energy=float("inf"), results=1, search_width=1000, Debug=False, Verbose=False):
    """
    indirect findpath, main function

    settings:
    indirect_iterations, default value 2 (means 1 direct pass, 1 indirect pass)

    """

    if Debug:
        coloredlogs.DEFAULT_LOG_FORMAT = '%(levelname)s %(message)s'
        coloredlogs.install(level='DEBUG')

    s1 = start_list

    s2 = destination_list[0]

    add_moves = []

    fp_class = Fp_class(sequence, s1, s2, add_moves)

    current_width = search_width  # for the time being, only 1 pass

    # generate move list

    fp_class.destinations = [[i, 0] for i in destination_list]

    fp_class.min_bp_dist = float("inf")
    fp_class.max_bp_dist = float("-inf")

    print_d(s1)
    print_d("destinations:")

    move_list = set()

    fp_class.available = dict()
    all_available = [set()] * len(destination_list)

    for a, s in enumerate(destination_list):
        bp_dist = RNA.bp_distance(s, s1)
        fp_class.destinations[a] = (s, bp_dist)

    fp_class.destinations.sort(key=lambda x: -x[1])

    for a, (s, bp_dist) in enumerate(fp_class.destinations):

        current_move_list = set()

        if bp_dist < fp_class.min_bp_dist:
            fp_class.min_bp_dist = bp_dist

        if bp_dist > fp_class.max_bp_dist:
            fp_class.max_bp_dist = bp_dist

        c_pt = fp_class.p_tables[s]
        pt1 = fp_class.p_tables[s1]

        for i in range(1, c_pt[0]):
            if pt1[i] != c_pt[i]:
                if i < pt1[i]:
                    # bp deletion
                    move_list.add((-i, -pt1[i]))
                    current_move_list.add((-i, -pt1[i]))

                if i < c_pt[i]:
                    # add bp
                    move_list.add((i, c_pt[i]))
                    current_move_list.add((i, c_pt[i]))

        # current_move_list.add((-69, -79))
        # current_move_list.add((-70, -78))
        # current_move_list.add((-71, -77))
        # current_move_list.add((69, 79))
        # current_move_list.add((70, 78))
        # current_move_list.add((71, 77))

        # current_move_list.add((26,  36))
        # current_move_list.add((27,  35))

        fp_class.available[a] = current_move_list
        all_available[a] = current_move_list.copy()

        print_d("dest:", a, s, bp_dist)
        print_d(len(current_move_list), current_move_list)
        # break

    destination_list = [i[0] for i in fp_class.destinations]

    # all of them combined
    fp_class.moves_add = move_list

    # One-Liner to intersect a list of sets

    intersection = all_available[0].intersection(*all_available)
    additional_moves = set()

    for a in all_available:
        for current_set in a:

            if current_set not in intersection:

                # add inverse move
                a = -current_set[0]
                b = -current_set[1]
                additional_moves.add((a, b))

    # print(intersection)
    # print ("add moves:", additional_moves)

    # add inverse moves to undo bs...

    for k, (s, bp_dist) in enumerate(fp_class.destinations):
        for a, b in additional_moves:
            if (-a, -b) in fp_class.available[k]:
                fp_class.available[k].add((a, b))

                # print (-a,-b)

    # destinations: start with the largest bp dist
    # print (fp_class.destinations)

    # all_moves[0] = move_list # combined

    # fp_class.available = np.zeros([len(destination_list), len(move_list)]).astype(bool)
    # # which moves are available where
    # for b, t in enumerate(move_list):
    #     for a in range(len(destination_list)):
    #         fp_class.available[a][b] = t in all_moves[a]

    # fp_class.available = all_moves
    # print (fp_class.available)

    max_en = 9999999999

    print_d("~FWD~~~~~~")
    result_dict = defaultdict(lambda: 9999)

    # fwd
    path_generator = fp_class.find_path_once(
        start_list, destination_list, max_energy, current_width, mode=True, sort_min=False, Debug=Debug, Verbose=Verbose)

    for path in path_generator:
        max_en = path.saddle_e

        end_s = RNA.db_from_ptable(path.p_table)  # ?

        if end_s not in destination_list:
            continue

        start_index = path.start_pt
        start_s = fp_class.destinations[start_index][0]

        # print_moves(sequence, s1, start_s, path.moves)

        if max_en < result_dict[end_s]:
            result_dict[end_s] = max_en

        # check variations

        start_s_index = destination_list.index(start_s)
        print_d("index:", start_s_index)

        for a in range(len(fp_class.available)):
            if a == start_s_index:
                continue

            start_s_moves = fp_class.available[start_s_index]
            other_moves = fp_class.available[a]
            diff = start_s_moves-other_moves

            # print ("~~", a, diff)

            print_d("to:", a, diff)
            # try to remove these moves, see if we get a better result
            moves_i_j = [(x[0], x[1]) for x in path.moves]
            new_max_en, last_s = print_moves(sequence, s1, start_s, moves_i_j, Verbose=False, ignore_moves=diff)

            if new_max_en < max_en:
                if RNA.bp_distance(last_s, destination_list[a]) != 0:
                    new_max_en_add = pathfinder.pathfinder(
                        sequence, last_s, destination_list[a], search_width=search_width, verbose=False).max_en
                    if new_max_en_add < new_max_en:
                        print("better result:", new_max_en, RNA.bp_distance(last_s, destination_list[a]), "no effect")
                else:
                    print("better result:", new_max_en, RNA.bp_distance(last_s, destination_list[a]))

        # fp_class.available[a]

    # for key in result_dict:
        # print("fwd:", key, result_dict[key])
# #

    if Debug:
        coloredlogs.DEFAULT_LOG_FORMAT = '%(levelname)s %(message)s'
        coloredlogs.install(level='DEBUG')

    print_d("~BWD~~~~~~")
    # max_energy = 999
    # result_dict = defaultdict(lambda: 9999)

    # path_generator = fp_class.find_path_once(
    #     start_list, destination_list, max_energy, current_width, mode=False, sort_min=False, Debug=Debug, Verbose=Verbose)

    # for path in path_generator:
    #     max_en = path.saddle_e

    #     end_s = RNA.db_from_ptable(path.p_table)

    #     start_index = path.start_pt
    #     start_s = fp_class.destinations[start_index][0]

    #     # start_s = 3
    #     # print (start_s)

    #     # print ("f", start_s, max_en, path.moves)
    #     # print_moves(sequence, start_s, end_s, path.moves)

    #     for e in path.embedded:
    #         embedded_en = path.embedded[e]
    #         if embedded_en <= max_en:
    #             em_s = fp_class.destinations[e][0]
    #             if max_en < result_dict[em_s]:
    #                 result_dict[em_s] = max_en
    #             # print ("e", e, path.embedded[e])

    #     if max_en < result_dict[start_s]:
    #         result_dict[start_s] = max_en

    # BWD END
    return_energy = float("inf")

    for key in result_dict:
        print("final:", key, result_dict[key])
        if result_dict[key] < return_energy:
            return_energy = result_dict[key]

    # code here to not just return nothing
    return return_energy
コード例 #5
0
                    rest = rest.replace('[', '').replace(']', '')
                    rest = rest.replace('{', '').replace('}', '')
                    rest = rest.replace(',', '')
                    rest = rest.split()
                    if len(rest)!=3:
                        # print (line)
                        continue
                    i, j, en = rest
                    i = int(i)
                    j = int(j)
                    en = float(en)
                    if en > max_en:
                        max_en = round(en, 2)
                    moves.append((i, j, en))
  
            print_moves(sequence, s1, s2, moves)


        

    sequence = row.sequence
    s1 = row.s1
    s2 = row.s2

    print ("\nregular findpath result:")
    pathfinder_result = pathfinder.pathfinder(sequence, s1, s2, search_width=search_width, verbose=True)
    # print ("regular findpath result:", pathfinder_result.max_en)


    # if index>0:
    #     break
コード例 #6
0
def find_path(sequence,
              s1,
              s2,
              add_moves=[],
              results=1,
              indirect_iterations=2,
              search_width=1000,
              Debug=False,
              Verbose=False):
    """
    indirect findpath, main function

    settings:
    indirect_iterations, default value 2 (means 1 direct pass, 1 indirect pass)

    """

    fp_class = Fp_class(sequence, s1, s2, add_moves)
    max_energy = float("inf")

    current_width = search_width  # for the time being, only 1 pass

    indirect_moves = [add_moves]
    best_max_en = float("inf")
    best_max_pos = 0
    best_path = False
    best_indirect_moves = []
    best_ptables = []
    best_indirect_move_count = 0

    for iteration in range(indirect_iterations):

        # first pass is direct, then iterate over different indirect moves

        next_indirect_moves = []

        for indirect_move in indirect_moves:

            if indirect_move == None:
                indirect_move = []  # first iteration only

            indirect_move = set(best_indirect_moves) | set(indirect_move)
            if Verbose:
                print("Iteration", iteration,
                      "launching findpath with addtional moves:",
                      indirect_move)

            # add a set of optional indirect moves to the direct move set, e.g. add {(6, 12), (5, 13)}
            fp_class.moves_add = indirect_move
            # main findpath_once function call with supplied settings
            path_generator = fp_class.find_path_once(s1,
                                                     s2,
                                                     max_energy,
                                                     current_width,
                                                     mode=True,
                                                     sort_min=False,
                                                     Debug=Debug,
                                                     Verbose=Verbose)

            # iterate over all currently found paths. somepaths might not be optimal
            for path in path_generator:
                # path is an intermediate struct, containing saddle_e, moves, etc.

                if path.saddle_e < max_energy:
                    max_energy = path.saddle_e

                e_0 = fp_class.evals[s1]
                e_1 = fp_class.evals[s2]
                current_ptable = list(fp_class.p_tables[s1])

                ptables = [
                ]  # list of ptables according to moves, should not be needed later

                # workaround convert moves to list of ptables, del this later
                current_used_indirect_moves = [
                ]  # which indirect moves are actually used
                current_moves = []
                for pos, (i, j, e) in enumerate(path.moves):
                    current_moves.append((i, j))
                    if (i, j) in indirect_move:
                        current_used_indirect_moves.append((i, j))
                    if i < 0:
                        current_ptable[-i] = 0
                        current_ptable[-j] = 0
                    else:
                        current_ptable[i] = j
                        current_ptable[j] = i
                    ptables.append(current_ptable.copy())

                # save best path for print output / next iteration
                if max_energy < best_max_en or \
                   (max_energy == best_max_en and len(current_used_indirect_moves) < best_indirect_move_count):
                    # or save best path with same energy, but fewer indirect moves: take this one instead

                    best_indirect_move_count = len(current_used_indirect_moves)
                    best_max_en = max_energy
                    best_path = path.moves.copy()
                    best_ptables = ptables.copy()
                    best_indirect_moves = current_used_indirect_moves.copy()
                    barrier = max_energy - e_0
                    if Verbose:
                        print(
                            f"New best result: {max_energy:6.2f} kcal/mol | B: {barrier:6.2f} kcal/mol | E[start]:{e_0:6.2f} E[end]:{e_1:6.2f} | additional moves: {current_used_indirect_moves}"
                        )

                if iteration + 1 != indirect_iterations:  # dont find new indirect moves in the last iteration

                    for current_indirect_moves in fp_class.find_stack(
                            ptables, current_moves):
                        # print ("find move", current_indirect_moves, next_indirect_moves)
                        if current_indirect_moves not in next_indirect_moves:
                            next_indirect_moves.append(current_indirect_moves)

        # print path during last iteration
        if iteration + 1 == indirect_iterations and Verbose:
            print_moves(sequence, s1, s2, best_path)
        # prepare for next indirect iteration
        else:
            # print ("found indirect moves:")
            # print (next_indirect_moves)
            indirect_moves = next_indirect_moves

        # best_path = [(0, 0), (-31, -45), (-35, -41), (-34, -42), (-33, -43),
        #  (-32, -44), (-5, -11), (-4, -12), (6, 12), (7, 11),
        #  (-3, -13), (5, 13), (-2, -14), (-1, -15), (4, 42), (3, 43), (2, 44), (1, 45),
        #  (-5, -13),(5, 41), (-6, -12), (6, 40), (-7, -11), (7, 39),
        #  (8, 38), (9, 37), (10, 36)]

    # post processing - check every indirect move -
    # confirm if they're actually useful (linear time)

    best_path_indirect_moves = []
    # check which indirect moves were actually used
    filtered = [(i[0], i[1]) for i in best_path]
    for i, j in filtered:
        if (-i, -j) in filtered and (
                -i, -j) not in best_path_indirect_moves and (i, j) != (0, 0):
            best_path_indirect_moves.append((i, j))

    indirect_moves = best_path_indirect_moves.copy()
    for i, j in best_path_indirect_moves:
        current_test = []
        for m, n, e in best_path:
            # if (-i, -j) in filtered: continue
            if (m, n) in filtered and (-m, -n) in filtered: continue
            current_test.append((m, n))
        test_en = print_moves(sequence, s1, s2, current_test, Verbose=False)
        if test_en == best_max_en:
            filtered.remove((i, j))
            filtered.remove((-i, -j))
            indirect_moves.remove((i, j))

    # code here to not just return nothing
    return best_max_en, filtered, indirect_moves
コード例 #7
0
def find_path(sequence,
              s_ref,
              destination_list,
              max_energy=float("inf"),
              results=1,
              search_width=1000,
              Debug=False,
              Verbose=False):
    """
    indirect findpath, main function

    settings:
    indirect_iterations, default value 2 (means 1 direct pass, 1 indirect pass)

    """

    if Debug:
        coloredlogs.DEFAULT_LOG_FORMAT = '%(levelname)s %(message)s'
        coloredlogs.install(level='DEBUG')

    s1 = s_ref
    pt1 = list(RNA.ptable_from_string(s1))
    # generate move list

    destination_list.sort()

    moves_dest = [set() for i in destination_list]
    moves_dest_add = [set() for i in destination_list]

    bp_dist_dest = [None for i in destination_list]
    pt_dest = [None for i in destination_list]

    min_bp_dist = float("inf")
    max_bp_dist = float("-inf")

    print_d(s_ref)
    print_d("destinations:")

    for a, s in enumerate(destination_list):
        bp_dist = RNA.bp_distance(s, s_ref)

        current_move_list = set()

        c_pt = list(RNA.ptable_from_string(s))
        pt_dest[a] = c_pt

        for i in range(1, c_pt[0]):
            if pt1[i] != c_pt[i]:
                if i < pt1[i]:
                    # bp deletion
                    current_move_list.add((-i, -pt1[i]))

                if i < c_pt[i]:
                    # add bp
                    current_move_list.add((i, c_pt[i]))

        moves_dest[a] = current_move_list.copy()

        bp_dist = len(current_move_list)
        bp_dist_dest[a] = bp_dist

        if bp_dist < min_bp_dist:
            min_bp_dist = bp_dist

        if bp_dist > max_bp_dist:
            max_bp_dist = bp_dist
        print_d("dest:", a, s, bp_dist)
        print_d(len(current_move_list), current_move_list)
        # break

    # One-Liner to intersect a list of sets

    all_moves = moves_dest[0].union(*moves_dest)
    common_moves = moves_dest[0].intersection(*moves_dest)

    print_d("common moves:", common_moves, len(common_moves))

    additional_moves = set()

    for a in range(len(moves_dest)):
        for current_set in moves_dest[a]:

            if current_set not in common_moves:

                # add inverse move
                i = -current_set[0]
                j = -current_set[1]
                moves_dest_add[a].add((-i, -j))
                # additional_moves.add((-a,-b))

        print_d("non-common moves", a, moves_dest_add[a],
                len(moves_dest_add[a]))

    # generate s_common from intersection moves

    pt_common = generate_end_s(pt1, common_moves)

    s_common = RNA.db_from_ptable(pt_common)
    print("bp dist common", RNA.bp_distance(s1, s_common), len(common_moves))

    print_d(s1)
    print_d(s_common)

    search_width = 20
    # Verbose = False
    Verbose = True

    r = pathfinder_cpp.find_path(sequence,
                                 s1,
                                 s_common,
                                 search_width=search_width,
                                 Verbose=Verbose)

    common_move_list = list(reversed(
        r.paths))[0:-1]  # back to front, skip the 0,0 move
    common_move_list = r.paths[1:]

    print("common moves:", len(common_move_list), common_move_list)

    add_moves = moves_dest_add[0]

    print("add moves", len(add_moves), add_moves)

    print(moves_dest[a] - common_moves)

    pt_d0 = generate_end_s(pt_dest[0], common_moves)
    s_d0 = RNA.db_from_ptable(pt_d0)

    s0 = destination_list[0]

    r0 = pathfinder_cpp.find_path(sequence,
                                  s_common,
                                  s0,
                                  search_width=search_width,
                                  Verbose=Verbose)

    # r = pathfinder_cpp.find_path(sequence, s1, s0, search_width=search_width, Verbose=Verbose)
    # return
    # import merge_cpp
    # merge_search_width = 10
    # merge_cpp.merge_findpath(sequence, s1, s0, r, r0, [],[], Debug=Debug, Verbose=Verbose, merge_search_width=merge_search_width)

    print("fp once")

    all_paths = []
    for path in fp_once(sequence, s1, s0, max_energy, search_width,
                        common_move_list, add_moves, True):
        all_paths.append(path)

    all_paths.sort(key=lambda x: x.saddle_e)

    # print (all_paths[0])

    print_moves(sequence, s1, s2, all_paths[0].moves)

    return

    intersection = intersection.union(additional_moves)
    # print(intersection)
    # print ("add moves:", additional_moves)

    fp_class.moves_add = intersection.copy()
    # add inverse moves to undo bs...

    for k, (s, bp_dist) in enumerate(fp_class.destinations):
        for a, b in additional_moves:
            if (-a, -b) in fp_class.available[k]:
                fp_class.available[k].add((a, b))
                # print (-a,-b)

    # destinations: start with the largest bp dist
    # print (fp_class.destinations)

    # all_moves[0] = move_list # combined

    # fp_class.available = np.zeros([len(destination_list), len(move_list)]).astype(bool)
    # # which moves are available where
    # for b, t in enumerate(move_list):
    #     for a in range(len(destination_list)):
    #         fp_class.available[a][b] = t in all_moves[a]

    # fp_class.available = all_moves
    # print (fp_class.available)

    # max_en = 9999999999

    print_d("~FWD~~~~~~")
    result_dict = defaultdict(lambda: 9999)

    # fwd
    path_generator = fp_class.find_path_once(start_list,
                                             destination_list,
                                             max_energy,
                                             current_width,
                                             mode=True,
                                             sort_min=False,
                                             Debug=Debug,
                                             Verbose=Verbose)

    for path in path_generator:
        max_en = path.saddle_e

        end_s = RNA.db_from_ptable(path.p_table)  # ?

        # if end_s not in destination_list:
        # continue

        start_index = path.start_pt
        start_s = fp_class.destinations[start_index][0]

        # print_moves(sequence, s1, start_s, path.moves)

        if max_en < result_dict[end_s]:
            result_dict[end_s] = max_en

    for key in result_dict:
        print("fwd:", key, result_dict[key])


# #

    if Debug:
        coloredlogs.DEFAULT_LOG_FORMAT = '%(levelname)s %(message)s'
        coloredlogs.install(level='DEBUG')

    print_d("~BWD~~~~~~")
    max_energy = 999
    # result_dict = defaultdict(lambda: 9999)

    # path_generator = fp_class.find_path_once(
    #     start_list, destination_list, max_energy, current_width, mode=False, sort_min=False, Debug=Debug, Verbose=Verbose)

    # for path in path_generator:
    #     max_en = path.saddle_e

    #     end_s = RNA.db_from_ptable(path.p_table)

    #     start_index = path.start_pt
    #     start_s = fp_class.destinations[start_index][0]

    #     # start_s = 3
    #     # print (start_s)

    #     # print ("f", start_s, max_en, path.moves)
    #     # print_moves(sequence, start_s, end_s, path.moves)

    #     for e in path.embedded:
    #         embedded_en = path.embedded[e]
    #         if embedded_en <= max_en:
    #             em_s = fp_class.destinations[e][0]
    #             if max_en < result_dict[em_s]:
    #                 result_dict[em_s] = max_en
    #             # print ("e", e, path.embedded[e])

    #     if max_en < result_dict[start_s]:
    # result_dict[start_s] = max_en

    # BWD END
    return_energy = float("inf")

    for key in result_dict:
        print("final:", key, result_dict[key])
        if result_dict[key] < return_energy:
            return_energy = result_dict[key]

    # code here to not just return nothing
    return return_energy