problem.addcbprenode
problem.addcbprenode |
Purpose
Declares a preprocess node callback function, called before the LP relaxation of a node has been optimized, so the solution at the node will not be available. This callback function will be called in addition to any callbacks already added by addcbprenode.
Synopsis
problem.addcbprenode (callback, data, priority)
nodinfeas = callback (my_prob, my_object)
Arguments
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callback
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The callback function, which takes three arguments,
my_prob,
my_object and
nodinfeas, and has no return value. This function is called before a node is reoptimized and the node may be made infeasible by setting
*nodinfeas to
1.
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my_prob
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The problem passed to the callback function,
callback.
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my_object
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The user-defined object passed as
object when setting up the callback with
addcbprenode.
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nodinfeas
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The feasibility status. If set to a nonzero value by the user, the current node will be declared infeasible by the Optimizer.
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data
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A user-defined object to be passed to the callback function,
callback.
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priority
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An integer that determines the order in which multiple preprocess node callbacks will be invoked. The callback added with a higher priority will be called before a callback with a lower priority. Set to 0 if not required.
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Example
The following example notifies the user before each node is processed:
prob.addcbprenode (preNode, None, 0)
prob.mipoptimize ("")
The callback function might resemble:
def preNode (prob, object):
return 0 # set to 1 if node is infeasible
Related topics
problem.removecbprenode,
problem.addcbinfnode,
problem.addcbintsol,
problem.addcbnodecutoff,
problem.addcboptnode.