J is a general program for doing different tasks in optimization, data analysis, matrix computations and simulation.
It has also tools for handling splines and plotting figures. It is intended to be used mainly in different forestry related applications.
It will supersede previous linear programming software JLP .
The linear optimization functions in J are designed to solve efficiently Model I type of linear programming problems,
where there are several treatment schedules for management units and the goal is to select optimal schedule combinations with linear programming.
For instance, we may want to maximize net present value of future incomes, subject to constraints that the income level is
nondecreasing in each subregion and the total volume after planning period is above a minimum level. Constraints can be specified to domains, i.e., subsets of management units.
From version 2.0 onwards, J software is able to solve factory problems. In a factory problem, the transportations costs of different timber assortments
at specified time periods and capacities of factories at the same time periods are included in the problem definition.
New features in the latest released version 2.1
- domains in optimization problems including factories
- new options for the definition of large problems including only z-variable (ordinary linear programming problems)
- new objects for accessing the solution of problems
J is operated using text command lines, but it contains tools which make this kind of operation mode more efficient.
The software is console application and it is tested to run on Windows 7 and Windows XP operating systems.
J is freely available for teaching and research.
Commercial use or use in practical forest planning requires commercial license and annual license fees.
J users' guide 2.1 in pdf format is available here: J2.1_userguide.pdf
For further information please contact
Reetta Lempinen, reetta.lempinen @ luke.fi, tel. +358 29 532 5354