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CALLBACKCHECKTIMEWORKDELAY

Description
Minimum delay in work units between two consecutive executions of the CHECKTIME callback in the same solution process
Type
Double
Topic areas
Callback, Determinism
Values
0 
Callback delay is disabled - the callback is executed every time;
n>0 
Callback invocation if less than n work units, which may be a fraction of a work unit, have passed since the last invocation.
Default value
0
Note

The CHECKTIME callback may be invoked very often and can lead to an overhead. This control enables users to specify a minimum delay between two consecutive calls, such that the overhead becomes controllable. Note that WORK is accumulated deterministically during the search in contrast to TIME. Therefore, the callback invocation sequence with a positive CALLBACKCHECKTIMEWORKDELAY is reproducible across multiple invocations of the same search (same user controls, same problem) even on different machines. Note that the internal counter is reset at every invocation of a solution process via XPRSlpoptimize, XPRSmipoptimize, etc.

Note
The disadvantage of setting a delay in work units is that work increases less uniformly than time.
Note
While the related control CALLBACKCHECKTIMEDELAY specifies a delay in milliseconds, this double control allows delay specification of an arbitrary fraction of a work unit.
Affects routines
XPRSaddcbchecktime.
See also
WORKLIMIT, CALLBACKCHECKTIMEDELAY
Category
Control

Parent Topic Control Parameters

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