VRPTW example.

[torressa]

Is your feature request related to a problem? Please describe. Vehicle routing problem with time-windows example.

Describe the solution you'd like Implement Righini G. and Salani M. (2006) in examples/vrptw/.

Describe alternatives you've considered Initial outline:

from networkx import DiGraph
from numpy import array

class VRPTW:
    def __init__(self, some_args):
        self.G = DiGraph(directed=True, n_res=2)
        # Populate G. Resources represent
        # [monotone, \tau, time-window feasibility]
        # And nodes with for example
        self.G.add_node(1, data={"time-window": (1, 2)})
        self.G.add_node(2, data={"time-window": (1, 10)})
        self.G.add_edge(1, 2, data={"travel-time": 1.5}, weight=10)

    def custom_REF(self, cumulative_res, edge):
        new_res = array(cumulative_res)
        # your filtering criteria that changes the elements of new_res
        # For example:
        head_node, tail_node, egde_data = edge[0:3]
        # There's a better way of doing this
        head_node_w_data = list(
            node for node in self.G.nodes(data=True)
            if node[0] == head_node)[0]
        tail_node_w_data = list(
            node for node in self.G.nodes(data=True)
            if node[0] == tail_node)[0]
        a_j, b_j = tail_node_w_data[1]['data']['time-window'][0:]
        new_res[0] += 1  # Monotone
        new_res[1] += max(cumulative_res[1] + edge_data['travel-time'] +
                          edge_data['data']['travel-time'], a_j)  # \tau
        # Update time-window feasibility resource accordingly
        if new_res[1] <= b_j:
            new_res[2] = 0
        else:
            new_res[2] = 1
        return new_res

Additional context

[torressa]

Sweet! In a new repo https://github.com/Kuifje02/vrpy