Xpress-Optimizer and Xpress-SLP patch 27.01.17 for Xpress 7.8 is now available on the FTP and Box for Windows 64 and 32, Linux 64 and 32 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 sign change in quadratic constraints with equality sign.
* Fixed an issue where an integer variable used in quadratic terms was erroneously converted to a binary variable.
* Fixed a rare issue related to solving a system of linear equations.
* Fixed an issue where parallel dual simplex method may wrongly declare a numerical unstable problem as unfinished.
* Fixed an issue where a rotated second order cone may be taken with wrong variable signs.
* Improved objective scaling in the barrier algorithm.
* Improved behavior of the homogeneous barrier algorithm.
* Fixed an issue where a super optimal solution was created after a restart.
* Fixed an issue with XPRSpresolverow that could result in the right-hand side for a presolved row being returned undefined.
* Fixed an issue where the declared the problem to be infeasble during the root node processing.
* Fixed an issue with node-to-node dual reductions for MIPs with indicator constraints that could cause optimal valid solutions to be dropped.
* Fixed an issue in the disconnected component presolver w.r.t. sub-optimal solutions
* Fixed an issue in the disconnected component presolver for problems with very large objective values that in rare cases could result in the problem being declared infeasible.
Xpress-Nonlinear release notes:
* Fixed a problem related to numerical derivatives over fixed variables when presolve is disabled.
This is the latest Xpress-Optimizer and Xpress-SLP patch for the Xpress 7.8 release branch. Please note that it must be installed over a prior installation of FICO Xpress 7.8 and requires a valid Xpress 7.8 license.