Changes between Version 2 and Version 3 of CglProbing
 Timestamp:
 May 28, 2006 4:02:18 PM (13 years ago)
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CglProbing
v2 v3 14 14 15 15 * 2) If both ways are feasible, it can happen that [[BR]] 16 ** 2.1) setting x to 0 implies that y must be set to 1 and 16 ** 2.1) setting x to 0 implies that y must be set to 1 and[[BR]] 17 17 ** 2.2) setting x to 1 implies that y must be set to 1 [[BR]] 18 18 yielding again a column cut. (2.2 is not done in this code as there is no mechanism for returning the information.) 19 [[BR]] 20 More common is that21 ** 2.3) setting x to 0 implies that y must be set to 1 and22 ** 2.4) setting x to 1 implies that y must be set to 023 19 20 More common is that [[BR]] 21 ** 2.3) setting x to 0 implies that y must be set to 1 and[[BR]] 22 ** 2.4) setting x to 1 implies that y must be set to 0 [[BR]] 23 so we can substitute for y which might lead later to more powerful cuts. 24 24 25 25 * 3) When setting x to 1, a constraint went slack by c. 26 We can tighten the constraint ax + .... <= b (where a may be zero) to (a+c)x + .... <= b. If this cut is violated then it is 27 generated. 26 We can tighten the constraint ax + .... <= b (where a may be zero) to (a+c)x + .... <= b. If this cut is violated then is generated. 28 27 29 28 * 4) Similarly we can generate implied disaggregation cuts … … 37 36 38 37 The mode options are: 39 * 0) Only unsatisfied integer variables will be looked at. 40 If no information exists for that variable then 41 probing will be done so as a byproduct you "may" get a fixing 42 or infeasibility. This will be fast and is only available 43 if a snapshot exists (otherwise as 1). 44 The bounds in the snapshot are the ones used. 45 * 1) Look at unsatisfied integer variables, using current bounds. 46 Probing will be done on all looked at. 47 * 2) Look at all integer variables, using current bounds. 48 Probing will be done on all 38 * 0) Only unsatisfied integer variables will be looked at. If no information exists for that variable then probing will be done so as a byproduct you "may" get a fixing or infeasibility. This will be fast and is only available if a snapshot exists (otherwise as 1). The bounds in the snapshot are the ones used. 39 * 1) Look at unsatisfied integer variables, using current bounds. Probing will be done on all looked at. 40 * 2) Look at all integer variables, using current bounds. Probing will be done on all