Helper

pdppy.helper

Helper file contains all necessary helper functions for package. The functions are separated by module in which they are used.

Instances Helper Functions

choose_s_t_requests(k, nodes, seed)	Choose s, t, and request pairs pseudo-randomly from given nodes.
random_geo_graph_generator(k[, seed])	Generate a random geometric graph with 2 **k* + 2 nodes.
city_graph_generator(city)	Generate an OSMnx graph of city.

Algorithms Helper Functions

christofides_approx(G, source)	Christofides’ Algorithm: 1.5-factor TSP approximation
preorder_st_traversal(H, T)	Conducts a pre-ordered traversal of tree T with an s-t orientation.
valid_minor(T, node_set)	Helper function for two_tree_traversal.
contract_tree(T, node_set)	Helper function for valid_minor.
separation_oracle(m, where)	Helper function for branch_cut_integer_prog and linear_prog.
construct_tour(H, x_opt[, integer])	Construct tour graph from decision variables from optimization.

Plot Helper Functions

node_labels(dict_requests)	Create dict of nodes with node labels for plotting request number and type.
node_marker(H, node)	Return node_marker for plotting of nodes.
graph_routes(G, P)	Find routes and position of nodes for each edge in P.
plot_routes(G, Groutes)	Produce overlain plot of G and Groutes with specified style below.