Improved Integer Solver and Superior Ease-of-Use
The recently released LINGO 7.0 includes a number of significant enhancements and new features. Several of the enhancements focus on increasing the performance of the integer solver. This release also includes a number of modifications to improve ease of use and allow the user more control over the solution process.
New Enhanced Integer Solver
LINGO's integer solver has been completely revised and updated. The solver's new heuristic procedure often allows the solver to find good integer solutions in a fraction of the time of earlier versions. The new integer solver has been able to find solutions to some problems that were previously unsolvable in a reasonable amount of time.
Increased Technical Control and Flexibility
LINGO 7.0 provides the user with extraordinary control of the preprocessing and solution process on integer models. A number of new integer tolerances allow the user to tailor the solution strategy to their particular problem structure. Experimenting with nondefault values for these tolerances can significantly improve runtimes on some integer models. The new list of tolerances include:
- Strong branching
- Warm start LP solver
- Cold start LP solver
- Time before switching on relative optimality tolerance
- Maximum cut application passes
- Relative cuts limit
- Lifting cuts
- Plant location cuts
- Disaggregation cuts
- Lattice cuts
- Coefficient reduction cuts
- Greatest common divisor cuts
Model Easier to Read with Syntax Coloring
LINGO is now "syntax aware" making models easier to read and debug. The model editor turns keywords blue, comments green, and all other model text is displayed in black.
Expanded and Enhanced Options
A number of new options increasing ease-of-use are included in LINGO 7.0. These include:
- Automatic parenthesis matching: This new feature makes building and checking complex models easier. Place the cursor to the right of a parenthesis and LINGO displays the parenthesis and its mate in red.
- Implicit set formation: Some commonly used sets may now be input in an abbreviated, implicit fashion. For example, the months of the year may be represented by "Jan..Dec".
- Database password and user-id support: You may now input any database user-id and password at the start of your session. This avoids having to enter this information each time LINGO accesses a protected database.
Expanded Documentation
To help you get up and running quickly and easily, the LINGO 7.0 documentation now covers even more aspects of using the LINGO package. Sample code illustrating how to use the LINGO DLL to callback to your Visual Basic code when the solver is running is now included, as well as, an example on interfacing with an Oracle database.
New Quasi-Random Number Function
The new @QRAND() function may be used to generate a series of quasi-random numbers. A form of "stratified sampling" is used to generate the numbers and fill the entire attribute with numbers that are "super uniformly" distributed. That is, the numbers are more uniformly distributed than you would expect by chance.
