Xpress-Optimizer and Xpress-SLP patch 28.01.15 for Xpress 7.9

Document created by zsoltcsizmadia@fico.com on Aug 2, 2016
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Xpress-Optimizer and Xpress-SLP patch 28.01.15 for Xpress 7.9 is now available on FTP and Box for Windows 64 and 32, Linux 64 and 32 and Mac 64 from




Xpress-Optimizer release notes:


* Fixed an incorrect behavior of XPRSgetcols, XPRSgetcols64, XPRSgetrows, and XPRSgetrows64 that return wrong mstart[] if the requested number of nonzeroes is smaller than the number of coefficients in the requested columns/rows.

* Fixed an incorrect return status in functions that return solution-related information.

* Fixed an incorrect sign change in quadratic constraints with equality sign.

* Fixed an issue where primal simplex may perturb too frequent when it is stalling.

* Fixed an issue related to using scramble names with large instances.

* Fixed an issue where an integer variable used in quadratic terms was erroneously converted to a binary variable.

* Fixed an issue with node-to-node dual reductions for MIPs with indicator constraints that could cause optimal valid solutions to be dropped.

* Fixed a rare issue related to solving a system of linear equations.

* Relaxed the tolerances when rounding implied integer variables in the presence of small numerical issues, which could otherwise result in acceptable MIP solutions being cut off.


Xpress-Nonlinear release notes:


<No changes since 28.01.13>


This is the latest Xpress-Optimizer and Xpress-SLP patch for the Xpress 7.9 release branch. Please note that it must be installed over a prior installation of FICO Xpress 7.9 and requires a valid Xpress 7.9 license.