CPLEX cpxcb FRACCUT

This page is part of the CPLEX Manual. See CPLEX.

CPLEX Gomory fractional cut callback.

Called from TOMLAB /CPLEX during Gomory fractional cuts processing

This callback is enabled by setting callback(9) = 1 in the call to cplex.m, or P rob.M I P.callback(9) = 1 if using tomRun('cplex',...).

cpxcb FRACCUT is called with one argument, the cpxCBInfo progress information vector.

Contents of cpxCBInfo variable:

i cpxCBInfo(i)		- Value
-------------------------------------------------------------
1 BEST_INTEGER	        - obj. value  of  best  integer solution
2 BEST_REMAINING	- obj. value  of  best  remaining  node
3 NODE_COUNT		- total number of  nodes solved
4 NODES_LEFT	 	- number of  remaining  nodes
5 MIP_ITERATIONS	- total number of  MIP iterations
6 MIP_FEAS		- returns 1 if feasible solution exists;  otherwise, 0
7 CUTOFF		- updated  cutoff  value
8 CLIQUE_COUNT		- number of  clique cuts  added
9 COVER_COUNT		- number of  cover  cuts  added
10 DISJCUT_COUNT	- number of  disjunctive cuts  added
11 FLOWCOVER_COUNT	- number of  flow  cover  cuts  added
12 FLOWPATH_COUNT	- number of  flow  path  cuts  added
13 FRACCUT_COUNT	- number of  Gomory  fractional cuts  added
14 GUBCOVER_COUNT	- number of  GUB  cover  cuts  added
15 IMPLBD_COUNT		- number of  implied bound cuts  added
16 MIRCUT_COUNT		- number of  mixed integer rounding  cuts  added
17 PROBE_PHASE		- current phase of  probing  (0-3)
18 PROBE_PROGRESS	- fraction of  probing  phase completed  (0.0-1.0)
19 FRACCUT_PROGRESS  	- fraction of  Gomory  cut  generation for  the  pass completed  (0.0 - 1.0)
20 DISJCUT_PROGRESS  	- fraction of  disjunctive cut  generation for  the  pass completed  (0.0 - 1.0)
21 FLOWMIR_PROGRESS  	- fraction of  flow  cover  and MIR cut  generation for  the  pass completed  (0.0 - 1.0)
22 MY_THREAD_NUM	- identifier of  the  parallel thread  making this call (always  0)
23 USER_THREADS		- total number of  parallel threads  currently running  (always  1)

By returning a nonzero value from cpxcb FRACCUT, the user can terminate the optimization.

If modifying this file, it is recommended to make a copy of it which is placed before the original file in the MATLAB path.