Xpress Updates 9.5.5

Community Manager

1 year ago

Xpress Updates 9.5.5 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#955

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

Release Notes for 9.5.5

Xpress Optimizer 44.01.05

Fixed an issue which could cause significant performance degradation of the barrier algorithm on very large problems.
Fixed a problem where setting HEUREMPHASIS=0 would not disable the 'E' heuristic for problems with quadratic rows.
Fixed a problem where constant objective functions were not properly written to LP files.
Fixed a problem when reading MPS files with more than INT_MAX nonzeros. This used to give an OOM with negative size. It now works correctly.
Fixed a potential wrong answer bug that could show up in particular with parallel heuristics at the root node.
Fixed an integer overflow for models that have more than INT_MAX nonzeros.
Fixed a crash occurring on models with indicator constraints in rare circumstances.
Fixed an issue in the barrier algorithm which could affect the solution of SOCP problems.
MIPstatus and LPstatus are now reset upon problem changes so that XPRSoptimize will return correct solvestatus and solstatus even if a timelimit is hit before the actual optimization commences.
Fixed an issue that caused Insight Compute integration to fail if Visual Studio is not installed.

Xpress Nonlinear 44.01.05

Fixed an issue that could lead to variable bounds on binary variables being ignored when solving an MINLP with Knitro.
Fixed an issue potentially leading to a crash in heuristics.

Xpress Global 44.01.05

Fixed numerical issues in bound reduction for bilinear, quotient, and logarithm terms.
Fixed an issue in bound reduction that could result in reporting infeasibility.
Fixed an issue that could result in a crash during the reformulation phase.
Fixed an issue that could lead to an invalid relaxation of a MINLP.
Fixed an issue arising in reformulation with linear constraints.

Xpress Interfaces 44.01.05 (Python, R, Matlab, .NET, Java, C++, C)

Python
- Fixed a crash that sometimes occurred when calling problem.getslpsol() after a nonlinear solve.
- Fixed an issue where certain nonlinear sums produced an invalid expression that could lead to a crash.
- Fixed an error when creating a problem with no rows and providing an empty list for the row names.
- Fixed a SystemError when accessing an unknown control or attribute.
- Fixed a problem where using xpress.init() as a context manager would not call xpress.free() if an exception was raised.
- Fixed a TypeError when slicing a Pandas data frame containing xpress.expression objects.
.NET, Java, C++
- Fixed some problems with empty and singleton expressions in the object based APIs.
Matlab
- On Linux, MEX files are now created in a way so that Xpress libraries can be found without setting LD_LIBRARY_PATH.