CVS log for pkgsrc/math/glpk/distinfo

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Default branch: MAIN
Current tag: pkgsrc-2017Q4

Revision 1.39 / (download) - annotate - [selected], Fri Aug 18 21:47:51 2017 UTC (6 years, 8 months ago) by adam
Branch: MAIN
CVS Tags: pkgsrc-2019Q2-base, pkgsrc-2019Q2, pkgsrc-2019Q1-base, pkgsrc-2019Q1, pkgsrc-2018Q4-base, pkgsrc-2018Q4, pkgsrc-2018Q3-base, pkgsrc-2018Q3, pkgsrc-2018Q2-base, pkgsrc-2018Q2, pkgsrc-2018Q1-base, pkgsrc-2018Q1, pkgsrc-2017Q4-base, pkgsrc-2017Q4, pkgsrc-2017Q3-base, pkgsrc-2017Q3
Changes since 1.38: +6 -6 lines
Diff to previous 1.38 (colored)

GLPK 4.63:

A "smart" LP perturbation was implemented in the primal and
dual simplex solvers. Now LP is perturbed only if it is
necessary, and by default perturbation is not activated.
The sum of primal infeasibilites that appears in the terminal
output of the primal simplex solver (as "inf = ...") now
corresponds to the original bounds of variables. This allows to
see how much perturbed solution violates the original bounds.

The long-step technique was implemented for phase I of the
primal simplex solver. This feature can be enabled by
specifying --flip option for glpsol or by specifying
glp_smcp.r_test = GLP_RT_FLIP on api level. For many LP
instances the long-step technique allows reducing the number
of simplex iterations to 30-70%. Please note that unlike the
dual simplex, where this technique can be used on both phase I
and II, for the primal simplex it can be used only on phase I,
where the sum of primal infeasibilities (which is a convex
piecewise linear function) is minimized.

An internal objective scaling was included in both primal and
dual simplex solvers. For many LP/MIP instances this feature
improves numerical stability (for the dual solver) and prevents
cycling near the optimum (for the primal solver).

The Posix version of glp_time (glpk/src/env/time.c) was changed
to resolve time_t issue on msys2.

Three new example models in MathProg were added:
life_goe.mod (Conway's Game of Life garden of eden checker);
tiling.mod (Rectifiable polyomino tilings generator);
toto.mod (Covering code generator).

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