Xpress Updates 9.5.6

Community Manager

1 year ago

Xpress Updates 9.5.6 is now available on the client area for Windows, Linux, and MacOS on x86-64, and Linux and MacOS on AArch64, from
https://clientarea.xpress.fico.com/download_patch.php#956

This is the latest updates for the Xpress 9.5 release branch, respectively, and require matching licenses. Please note that these archives must be extracted over a prior installation of FICO Xpress 9.5, respectively.

Release Notes for 9.5.6

Xpress Optimizer 44.01.06

Fixed an error condition when loading an almost empty problem.
Fixed an issue in the linearization of binary QPs that could lead to incorrect solutions.
Fixed an integer overflow in cut lifting.
Fixed problems when reading/writing compressed files with certain external tools on Windows.
Fixed an issue with mixed integer Gomory cuts for problems with semi-continuous variables, which could result in invalid cuts being created.
Fixed an issue in the quadratic primal simplex algorithm which could result in incorrect solutions.
Fixed an issue with general constraints where the same column appears multiple times as an input.
Fixed an issue with user solutions for second-order-cone-convertible quadratics.

Xpress Nonlinear 44.01.06

Fixed a crash when all indicator constraints could be removed during nonlinear presolve.
Fixed an issue with the transformation of non-convex quadratic objectives.

Xpress Global 44.01.06

Fixed a potential crash when adding partial solution to global solves via XPRSaddmipsol.

Xpress Interfaces 44.01.06 (Python, R, Matlab, .NET, Java)

Python
- Improved performance of problem.addrows, problem.addcols and problem.loadproblem, when names are provided. (Previously stated as fixed in 9.5.1, incorrectly.)
- Fixed an issue where after reading a problem from an MPS or LP file, the Python objects representing special ordered sets were inconsistent with the Optimizer problem.
- Removed internal controls and attributes that should not have been exposed in the Python interface.
- Added missing class attributes xpress.linterm, xpress.quadterm and xpress.nonlin.
- Fixed a problem where problem.addVariable did not fully revert the new variables if an error occurred while adding them to the problem.
- Fixed a problem where problem.addSOS did not set the names of the sets.
- Fixed a memory corruption issue in problem.addVariables.
- When restoring into an empty or linked problem, problem.restore() now recreates all variable/constraint/sos objects to match the dimensions of the restored problem. For unlinked problems, the legacy behaviour of keeping the existing model objects is preserved.