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HEURSEARCHZEROOBJSTRATEGY

Description
Strategy control for the Zero Objective ( Z) large neighborhood search heuristic, an LNS heuristic without an objective function. Called seldom and only when no feasible solution is available.
Type
Integer
Topic area
Heuristics
Values
-2 
XPRS_HEURSEARCHSTRATEGY_AUTOENFORCED Automatic enforced. The Optimizer determines the frequency and effort of this heuristic, ignoring the value of HEURSEARCHSTRATEGY.
-1 
XPRS_HEURSEARCHSTRATEGY_AUTOMATIC Automatic. The Optimizer determines the frequency and effort of this heuristic.
0 
XPRS_HEURSEARCHSTRATEGY_OFF Disabled.
1 
XPRS_HEURSEARCHSTRATEGY_CONSERVATIVE Conservative strategy; the heuristic is run less frequently than the default.
2 
XPRS_HEURSEARCHSTRATEGY_MODERATE Moderate strategy; default level of frequency and effort.
3 
XPRS_HEURSEARCHSTRATEGY_AGGRESSIVE Aggressive strategy; the heuristic is run more frequently than the default.
Default value
-1
Notes
At a moderate strategy, the LNS heuristics obey any user-specified value for HEURSEARCHROOTCUTFREQ and/or HEURSEARCHFREQ exactly. However, setting an LNS heuristic to a conservative (aggressive) strategy will lead to a less (more) frequent execution during the root cut loop and/or during the tree search than mandated by the frequency controls. Note that the effective frequency and effort applied by the chosen strategy are also influenced by HEUREMPHASIS.
The control value -2 ( XPRS_HEURSEARCHSTRATEGY_AUTOENFORCED) behaves like automatic selection (value -1, XPRS_HEURSEARCHSTRATEGY_AUTOMATIC), but, unlike -1, the value -2 is not overridden by the meta control HEURSEARCHSTRATEGY. For instance, setting 
    HEURSEARCHSTRATEGY = 0
    HEURSEARCHZEROOBJSTRATEGY = -2
will disable all other LNS heuristics, but enforce the default behavior of the Z heuristic.
Affects routines
XPRSmipoptimize ( MIPOPTIMIZE).
See also
HEURSEARCHSTRATEGY, HEUREMPHASIS, HEURSEARCHEFFORT, HEURSEARCHROOTCUTFREQ, HEURSEARCHFREQ.
Category
Control

Parent Topic Control Parameters

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