main_vrp.cpp File Reference

Detailed Description

main file for VRP pricer example

Author

Andreas Bley

Marc Pfetsch

We want to solve the vehicle routing problem on a graph G = (V,E) with V = J cup {d}, where d is the depot and the distances are given by the length function l_e: E -> R_{>= 0}.

Consider the MIP formulation

min sum_{e in E} l_e y_e s.t. -y_e + sum_{t in T_k} a^t_e x_t <= 0, for all e in E sum_{t in T_k} a^t_j x_t == 1, for all j in J y(delta(j)) == 2, for all j in J y_e in {0,1,2}, for all e in E x_t in [0,1], for all t in T_k

where T_k is the set of tours visiting at most k customers with repetitions of customers allowed and a^t_e (a^t_j) counts how often edge e (node j) is traversed in t in T_k.

Examples and the file format are given at https://neo.lcc.uma.es/vrp/vrp-instances/capacitated-vrp-instances/.

Definition in file main_vrp.cpp.

#include <stdio.h>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include "objscip/objscip.h"
#include "objscip/objscipdefplugins.h"
#include "pricer_vrp.h"

Go to the source code of this file.

Functions
static int	read_problem (const char *filename, int &num_nodes, int &capacity, vector< int > &demand, vector< vector< int > > &dist)
static SCIP_RETCODE	execmain (int argc, char **argv)
int	main (int argc, char **argv)

Function Documentation

read_problem()

static int read_problem ( const char *  filename, int &  num_nodes, int &  capacity, vector< int > &  demand, vector< vector< int > > &  dist  )

static

read VRP problem

Parameters

filename	filename
num_nodes	number of nodes in instance
capacity	capacity in instance
demand	array of demands of instance
dist	distances between nodes

Definition at line 63 of file main_vrp.cpp.

References x, and y.

Referenced by execmain().

execmain()

static SCIP_RETCODE execmain ( int  argc, char **  argv  )

static

Definition at line 232 of file main_vrp.cpp.

References BMScheckEmptyMemory, FALSE, NULL, read_problem(), SCIP_CALL, SCIP_INVALIDDATA, SCIP_OKAY, SCIP_PARAMETERUNKNOWN, SCIP_READERROR, SCIP_Real, SCIP_VARTYPE_INTEGER, SCIPactivatePricer(), SCIPaddCoefLinear(), SCIPaddCons(), SCIPaddVar(), SCIPcreate(), SCIPcreateConsLinear(), SCIPcreateProb(), SCIPcreateVar(), SCIPfindPricer(), SCIPfree(), SCIPincludeDefaultPlugins(), SCIPincludeObjPricer(), SCIPinfinity(), SCIPinfoMessage(), SCIPprintBestSol(), SCIPprintStatistics(), SCIPprintVersion(), SCIPreleaseCons(), SCIPreleaseVar(), SCIPsetIntParam(), SCIPsnprintf(), and SCIPsolve().

Referenced by main().

main()

int main	(	int	argc,
		char **	argv
	)

Definition at line 479 of file main_vrp.cpp.

References execmain(), and SCIP_OKAY.