ARMLIB 0.1

Description

This library is a collection of spatially constrained forest harvest scheduling problems. The problems are instances of the Area Restriction Model (ARM) and are mostly based on datasets from the Forest Management Optimization Site (FMOS).

The objective of the ARMLIB collection is to serve as a repository of ARM instances used in the literature. In addition, we hope the collection will stimulate research in the area by presenting challenging instances in similar way to what MIPLIB has done for the mixed integer programming comunity.

The current maintainers of the collection are Marcos Goycoolea and Juan Pablo Vielma. If you have any questions or suggestions or if you would like to contribute an instance please send a message to

Version 0.1

Version 0.1 is the first version of ARMLIB. Its main objective is to introduce the file format of the collection, provide some illustrative instances and encourage the comunity to share their instances in this format.

File format

ARMLIB distinguishes between DataSets and Instances. DataSets include the characteristics of a forest map such as stand attributes and adjacency relations between stands. DataSets of ARMLIB are usually directly obtained from an FMOS datasets by maybe fixing some assumptions about stand attributes or adjacency definitions. DataSets are composed of a directory or folder containing several files describing the DataSet.

Instances describe exactly the ARM problem that should be solved. An Instance is based in a particular DataSet and describes the objective and constraints of the ARM problem to be solved. An instance is composed of a file with a .arm extension. ARMLIB DataSets and Instances formats are described in detail in the following pdf file.

ARMLIB 0.1 File Format

A simple example of the file format and other auxiliary material such as scripts, tutorials and MPS files of some mixed integer programming formulations of the instances can be found here.

DataSets and Instances

The following table includes the DataSets of the ARMLIB 0.1 collection. Each compressed file contains the DataSet and a series of instances associated to it. The file also includes the best known solution for each of the instances and a file with extension .info describing how the DataSet was generated.

DataSet Base FMOS dataset
eldorado15A El Dorado
NBCL5A NBCL5

Instance difficulty

The following table includes a list of the instances in ARMLIB 0.1 and their associated dificulty. An instance is cosidered very easy if at least one of its possible integer programming formulations can be solved to optimality (0.01% GAP) by a commercial solver in less than 100 seconds. It is considered easy it can be solved to optimality in less than 10,000 seconds, it is considered hard if a gap close to 1% can be achieved in less than 10,000 seconds and it is considered very hard if it does not comply with any of the previous criteria.

Instance Base DataSet Difficulty Best Solution Best Upper Bound
eldorado15A_1_line.arm eldorado15A very easy 2154060 2154060
eldorado15A_3_line.arm eldorado15A hard 3302746 3307361
eldorado15A_5_line.arm eldorado15A easy 3628045 3628405
eldorado15A_12_line.arm eldorado15A very easy 3757796 3758017
eldorado15A_3_line_vol_age.arm eldorado15A easy 3089388 3089694
eldorado15A_5_line_vol_age.arm eldorado15A hard 3458583 3459444
eldorado15A_12_line_vol_age.arm eldorado15A hard 3674355 3690894
NBCL5A_3_line_2Vol_Age40.arm NBCL5A easy 302224364 302254343
NBCL5A_3_line_4Vol_Age40.arm NBCL5A hard 296584400 296609345
NBCL5A_3_line_TotalVol_Age40.arm NBCL5A easy 304272936 304286495
NBCL5A_9_line_2Vol_Age40.arm NBCL5A hard 310905021 311864456
NBCL5A_9_line_4Vol_Age40.arm NBCL5A hard 302478139 306696569
NBCL5A_9_line_TotalVol_Age40.arm NBCL5A easy 313163137 313192630