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MIPPRESOLVE

Description
Branch and Bound: Type of integer processing to be performed at nodes. If set to 0, no processing will be performed. This is a bit-vector control (see Section Bit-vector controls).
Type
Integer
Topic areas
Presolve, Branch and Bound Search, Bit-vector
Values
Bit
Meaning
0 
Reduced cost fixing will be performed at each node. This can simplify the node before it is solved, by deducing that certain variables' values can be fixed based on additional bounds imposed on other variables at this node. This bit is deprecated, use NODEREDCOSTTIGHTEN instead.
1 
Primal reductions will be performed at each node. Uses constraints of the node to tighten the range of variables, often resulting in fixing their values. This greatly simplifies the problem and may even determine optimality or infeasibility of the node before the simplex method commences. This bit is deprecated, use NODEAPPLIEDBOUNDS instead.
3 
If node preprocessing is allowed to change bounds on non MIP entities (e.g., continuous) columns. This bit is deprecated, use NODEAPPLIEDBOUNDS instead.
4 
Dual reductions will be performed at each node. This bit is deprecated, use NODEDUALREDUCTIONS instead.
5 
Allow global (non-bound) tightening of the problem during the tree search.
6 
The objective function will be used to find reductions at each node.
7 
[Unused] This bit is no longer used to control restarts. Refer to the integer control MIPRESTART for disabling tree restarts.
8 
Allow that symmetry is used to presolve the node problem.
Default value
-1
Notes
1. A value of -1 enables all individual bits.
2. You can control whether node presolve is applied, and at which level, with the control NODEPRESOLVE. The most common node presolve reductions also have a dedicated control, like NODEREDCOSTTIGHTEN. This bit-vector control allows you a more fine-grained control on which (less common) reductions are enabled or not.
Affects routines
XPRSmipoptimize ( MIPOPTIMIZE).
See also
NODEPRESOLVE, NODEREDCOSTTIGHTEN, NODEAPPLIEDBOUNDS, NODEDUALREDUCTIONS, NODEPROBINGEFFORT.
Category
Control

Parent Topic Control Parameters

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