Initializing help system before first use

# addcbgapnotify

Purpose
Declares a gap notification callback, to be called when a MIP solve reaches a predefined target, set using the MIPRELGAPNOTIFY, MIPABSGAPNOTIFY, MIPABSGAPNOTIFYOBJ and/or MIPABSGAPNOTIFYBOUND controls.
Synopsis
`addcbgapnotify(prob, cb, prio = 0)`
Arguments

prob | The problem pointer to which the callback is added.
cb | The callback function to add.
prio | The priority of the callback. If multiple callbacks are registered for the same event then they are invoked according to their priority ordering.

Return value
Always returns 0 (zero).
Further information
Note the general callback conventions:

- a callback function may return either an integer or a list.
- if the C callback function has an integer return type then the value returned to the optimizer is the integer value returned or the list's "ret" element (if it exists).
- if the C callback function has output arguments then these arguments are taken from the list that is returned by the callback function.
- the R callback function will only receive the input arguments of the C callback

The gapnotify callback supports the following input arguments (in this order):

cbprob
  The current problem.
relgapnotifytarget
  The value the MIPRELGAPNOTIFY control will be set to after this callback. May be modified within the callback in order to set a new notification target.
absgapnotifytarget
  The value the MIPABSGAPNOTIFY control will be set to after this callback. May be modified within the callback in order to set a new notification target.
absgapnotifyobjtarget
  The value the MIPABSGAPNOTIFYOBJ control will be set to after this callback. May be modified within the callback in order to set a new notification target.
absgapnotifyboundtarget
  The value the MIPABSGAPNOTIFYBOUND control will be set to after this callback. May be modified within the callback in order to set a new notification target.

The gapnotify callback supports the following output arguments:

ret
  An integer that will interrupt the search if non-zero.
relgapnotifytarget
  The value the MIPRELGAPNOTIFY control will be set to after this callback.
absgapnotifytarget
  The value the MIPABSGAPNOTIFY control will be set to after this callback.
absgapnotifyobjtarget
  The value the MIPABSGAPNOTIFYOBJ control will be set to after this callback.
absgapnotifyboundtarget
  The value the MIPABSGAPNOTIFYBOUND control will be set to after this callback.

Parent Topic R interface reference manual

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