def quick_shortest(graph):
    N = graph.N-1
    distances = {} 
    previous = {}
    
    previous[0] = None
    distances[N] = 0.0

    for idx in xrange(N-1,-1,-1):
        Q = priorityDictionary()
        for x in graph[idx]:
            Q[x] = graph[idx][x] + distances[x]
        
        small = Q.smallest()
        previous[idx] = small
        distances[idx] = Q[small]
    # get path from previous 21/08/13 09:10:14
    paths = []
    paths.append(0)
    start = 0
    while start < N:
        paths.append(previous[start])
        start = previous[start]
    return (distances, paths)
    


    
Example #2
0
def dijkstra(graph, node_start, node_end=None):
    distances = {}
    previous = {}
    Q = priorityDictionary()

    for v in graph:
        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        if v == node_end: break

        for u in graph[v]:
            cost_vu = distances[v] + graph[v][u]

            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v

    if node_end != None:
        return {
            'cost': distances[node_end],
            'path': path(previous, node_start, node_end)
        }
    else:
        return (distances, previous)
def dijkstra(graph, node_start, node_end=None):
    distances = {}      
    previous = {}       
    Q = priorityDictionary()
    
    for v in graph:
        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY
    
    distances[node_start] = 0
    Q[node_start] = 0
    
    for v in Q:
        if v == node_end: break

        for u in graph[v]:
            cost_vu = distances[v] + graph[v][u]
            
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v

    if node_end!=None:
        return {'cost': distances[node_end], 
                'path': path(previous, node_start, node_end)}
    else:
        return (distances, previous)
Example #4
0
def dp_graph(graph, node_start, node_end=None):
    N = graph.N
    distances = {}
    previous = {}

    previous[node_start] = None
    for idx in xrange(0, node_start + 1, 1):
        distances[idx] = 0.0

    for idx in xrange(node_start + 1, N, 1):
        Q = priorityDictionary()
        for x in graph[idx]:
            Q[x] = distances[x] + graph[idx][x]
        small = Q.smallest()
        if small < node_start:
            previous[idx] = node_start
        else:
            previous[idx] = Q.smallest()
        distances[idx] = Q[small]

    if node_end:
        return {
            'cost': distances[node_end],
            'path': path(previous, node_start, node_end)
        }
    else:
        return (distances, previous)
Example #5
0
def dijkstra(g, length_graph, node_start):
    distances = {}
    Q = priorityDictionary()
    visited = []

    for v in g:
        distances[v] = g.INFINITY
        Q[v] = g.INFINITY

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        visited.append(v)
        if len(visited) == length_graph:
            break

        for u in g[v]:
            if u in visited:
                continue

            cost_vu = distances[v] + g[v][u]

            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
    return distances
Example #6
0
def dp_graph(graph, node_start, node_end=None):
    N = graph.N
    distances = {} 
    previous = {}
    
    previous[node_start] = None
    for idx in xrange(0, node_start+1, 1):
        distances[idx] = 0.0

    for idx in xrange(node_start+1,N,1):
        Q = priorityDictionary()
        for x in graph[idx]:
            Q[x] = distances[x] + graph[idx][x]
        small = Q.smallest()
        if small < node_start:
            previous[idx] = node_start
        else:
            previous[idx] = Q.smallest()
        distances[idx] = Q[small]
    
    if node_end:
        return {'cost': distances[node_end], 
                'path': path(previous, node_start, node_end)}
    else:
        return (distances, previous)
Example #7
0
    def shortest_path(self, graph, node_start, node_end=UNDEFINED):
        INFINITY = 999
        UNDEFINED = None
        distances = {}
        previous = {}
        Q = priorityDictionary()
        # Q = {}
        # print(type(INFINITY))
        for v in graph:
            distances[v] = INFINITY
            previous[v] = UNDEFINED
            Q[v] = INFINITY

        distances[node_start] = 0
        Q[node_start] = 0

        for v in Q:
            if v == node_end:
                break

            for u in graph[v]:
                dist_vu = distances[v] + graph[v][u]

                if dist_vu < distances[u]:
                    distances[u] = dist_vu
                    Q[u] = dist_vu
                    previous[u] = v

        if node_end:
            return {
                'dist': distances[node_end],
                'path': self.path(previous, node_start, node_end)
            }
        else:
            return (distances, previous)
Example #8
0
    def Dijkstra(self, node_start, node_end=None):
        ###
        # Dijkstra's algorithm
        # only use part of the the graph, i.e. aGraph (in the approximity of startPt 
        # and endPt) to build Dict gDict in order to reduce complexity
        ###
        distances = {}      
        previous = {}       
        Q = priorityDictionary()
    
        for v in self.vertList:
            distances[v] = maxVal
            previous[v] = None
            Q[v] = maxVal
    
        distances[node_start] = 0
        Q[node_start] = 0
    
        for v in Q:
            if v == node_end: break

            for u in self.vertList[v].getConnections():
                cost_vu = distances[v] + self.vertList[v].connectedTo[u][0]            
                if u in self and cost_vu < distances[u]:
                    distances[u] = cost_vu
                    Q[u] = cost_vu
                    previous[u] = v

        if node_end:
            return {'dist': distances[node_end], 
                    'path': self.path(previous, node_start, node_end)}
        else:
            return (distances, previous)
Example #9
0
def dijkstra(g, length_graph, node_start):
    distances = {}
    Q = priorityDictionary()
    visited  = []

    for v in g:
        distances[v] = g.INFINITY
        Q[v] = g.INFINITY

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        visited.append(v)
        if len(visited) == length_graph:
            break

        for u in g[v]:
            if u in visited:
                continue
            
            cost_vu = distances[v] + g[v][u]
            
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
    return distances
Example #10
0
def dijkstra(graph, node_start, node_end=None, visited=[]):
    distances = {}      
    previous = {}       
    Q = priorityDictionary()
    visited_copy = deepcopy(visited)
    
    for v in graph:
        
        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY

        '''
        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY
        '''
        
    
    distances[node_start] = 0
    Q[node_start] = 0
    
    for v in Q:
        visited_copy.append(v)
        if v == node_end: break

        for u in graph[v]:
            if u in visited_copy:
                continue
            cost_vu = 0
            if distances[v] > graph[v][u]:
                cost_vu = distances[v]
            else:
                cost_vu = graph[v][u]

            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v
            '''
            cost_vu = distances[v] + graph[v][u]
            
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v
            '''
            

    if node_end != None:
        return {'cost': distances[node_end], 
                'path': path(previous, node_start, node_end)}
    else:
        return (distances, previous)
Example #11
0
def dijkstra(graph, node_start, node_end=None, visited=[]):
    distances = {}
    previous = {}
    Q = priorityDictionary()
    visited_copy = deepcopy(visited)

    for v in graph:

        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY
        '''
        distances[v] = graph.INFINITY
        previous[v] = graph.UNDEFINDED
        Q[v] = graph.INFINITY
        '''

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        visited_copy.append(v)
        if v == node_end: break

        for u in graph[v]:
            if u in visited_copy:
                continue
            cost_vu = 0
            if distances[v] > graph[v][u]:
                cost_vu = distances[v]
            else:
                cost_vu = graph[v][u]

            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v
            '''
            cost_vu = distances[v] + graph[v][u]
            
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v
            '''

    if node_end != None:
        return {
            'cost': distances[node_end],
            'path': path(previous, node_start, node_end)
        }
    else:
        return (distances, previous)
def dijkstra(graph, node_start, node_end=None):
    distances = {}
    previous = {}
    Q = priorityDictionary()


    for v in graph:
        for u in v.neighbors:
            distances[u] = inf
            previous[u] = None
            Q[u] = inf

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        if v == node_end: break
        v_node = graph.get_node(v)
        if not v_node.is_active():
            continue

        for u in v_node.neighbors:
            if not graph.get_node(u).is_active():
                continue
            edge = graph.get_edge(v,u)
            if not edge.is_active():
                continue
            cost_vu = distances[v] + edge.data.length

            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v

    if node_end:
        return {'cost': distances[node_end],
                'path': path(previous, node_start, node_end),
                'distances': distances}
    else:
        return (distances, previous)
Example #13
0
def dijkstra3(graph, node_start, node_end=None, all_paths=None):
    distances = {}
    previous = {}
    Q = priorityDictionary()
    for v in graph:
        distances[v] = DiGraph.INFINITY
        previous[v] = DiGraph.UNDEFINDED
        Q[v] = DiGraph.INFINITY
        for u in graph[v]:
            if u in distances:
                continue
            distances[u] = DiGraph.INFINITY

    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        if v == node_end: break
        if not graph[v]:
            continue
        for u in graph[v]:
            newcost = graph[v][u]
            for w in range(0, len(all_paths)):
                if u == all_paths[w]:
                    newcost = 100
            cost_vu = distances[v] + newcost
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v

    if node_end:
        return {
            'cost': distances[node_end],
            'path': path(previous, node_start, node_end)
        }
    else:
        return (distances, previous)
Example #14
0
def dijkstra(graph, node_start, node_end=None):
    #print"graph",graph
    #print node_start, node_end
    #node_start = node_start.encode('utf-8')
    #node_end = node_end.encode('utf-8')
    distances = {}      
    previous = {}       
    Q = priorityDictionary()

    for v in graph:
      ##print "-%s-"%v
      distances[v] = DiGraph.INFINITY
      previous[v] = DiGraph.UNDEFINDED
      Q[v] = DiGraph.INFINITY
      for u in graph[v]:
        if u in distances:
          continue 
        distances[u] = DiGraph.INFINITY
    
    distances[node_start] = 0
    Q[node_start] = 0

    for v in Q:
        if v == node_end: break
        if not graph[v]:
           continue
        for u in graph[v]:
            cost_vu = distances[v] + graph[v][u]
            if cost_vu < distances[u]:
                distances[u] = cost_vu
                Q[u] = cost_vu
                previous[u] = v
    if node_end:

        return {'cost': distances[node_end], 
                'path': path(previous, node_start, node_end)}
    else:
        return (distances, previous)
Example #15
0
def quick_shortest(graph):
    N = graph.N - 1
    distances = {}
    previous = {}

    previous[0] = None
    distances[N] = 0.0

    for idx in xrange(N - 1, -1, -1):
        Q = priorityDictionary()
        for x in graph[idx]:
            Q[x] = graph[idx][x] + distances[x]

        small = Q.smallest()
        previous[idx] = small
        distances[idx] = Q[small]
    # get path from previous 21/08/13 09:10:14
    paths = []
    paths.append(0)
    start = 0
    while start < N:
        paths.append(previous[start])
        start = previous[start]
    return (distances, paths)