MIP start. HiGHS 1.5 supports complete MIP starts only. For partial MIP start, user solve with fixed known variables first (Modeling Tip #7).
Wrong solver options are gracefully reported via solve_message.
Fixed solution status reporting to AMPL
Fixed basis input with obj offset or missing data
Added warm start for LP problems
Reading column names from col file is present
Changes in the MP library: added variable names support and removed spurious starting solution
Fixed a problem when retrieving basis status
Implemented retrieval of MIP gap so that if optimality is reached via presolving, the returned gap is 0
Updated to HiGHS 1.5.1; now returning number of LP iterations in a MIP solve
Fixed: now returning the correct dual values for the constraints
Updated to HiGHS 1.4.2
Fix for error encountered when passing variables status if variables with unknown basis status are present.
Changes in the MP library
Changes in MP
Updates for HiGHS 1.4.1
The run_crossover option has now values “on”, “off” and “choose”. The latter results in crossover being run if the result of IPM without crossover is imprecise
Changes in MP: added the ==> else operator Implemented implication with ‘else’: constr1 ==> constr2 [else constr3]
Changes in MP: PLApproxRelTol, PLApproxDomain Parameters to control piecewise-linear approximation. cvt:plapprox:reltol default value changed from 1e-5 to 0.01.
Piecewise-linear approximation of quadratics HiGHS accepts quadratic objectives. For nonconvex ones, set cvt:quadobj=0. Recognizing x^2 for stronger univariate approximation
Changes in MP: piecewise-linear approximations of nonlinear functions, default value of big-M
Fixed an issue with passing/retrieving basis information
First release of HiGHS for AMPL