Package io.github.lmores.tsplib

package io.github.lmores.tsplib
This package provides utilities to read files in TSPLIB format.

All files in TSPLIB format are supported, except those with extension .problems.

This package includes a copy of the TSPLIB archive taken from the official website.

As many types of problems in the TSPLIB assume that the underlying graph is complete, edges are not explicitly stored in memory when possible. In these cases, the only value associated with an edge is its weight. TSPLIB instance files have 13 different ways to encode edge weights (EXPLICIT, EUC_2D, EUC_3D, MAX_2D, MAX_3D, MAN_2D, MAN_3D, CEIL_2D, GEO, ATT, XRAY1, XRAY2 and SPECIAL). Out of all these possibilities, only the EXPLICIT one requires the direct enumeration of all weight values, whereas in all the other cases the weight is computed by a specific function using from the coordinates of the nodes.

Since the number of nodes can be high, when the edge weights format is different from EXPLICT, weight values are not stored in memory when an instance is loaded; instead, they are generated on the fly each time the method BaseInstance.getEdgeWeight(int, int) is called. You can obtain an in memory copy of all the edge weights using the method BaseInstance.materializeEdgeWeightsMatrix().

Since:
0.0.1
Author:
Lorenzo Moreschini