type_cons.h
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29 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 47 typedef struct SCIP_Conshdlr SCIP_CONSHDLR; /**< constraint handler for a specific constraint type */ 50 typedef struct SCIP_ConsData SCIP_CONSDATA; /**< locally defined constraint type specific data */ 51 typedef struct SCIP_ConsSetChg SCIP_CONSSETCHG; /**< tracks additions and removals of the set of active constraints */ 55 * If the copy process was a one to one the valid pointer can set to TRUE. Otherwise, you have to set this pointer to 56 * FALSE. In case all problem defining objects (constraint handlers and variable pricers) return a valid TRUE for all 57 * their copying calls, SCIP assumes that it is a overall one to one copy of the original instance. In this case any 58 * reductions made in the copied SCIP instance can be transfer to the original SCIP instance. If the valid pointer is 59 * set to TRUE and it was not one to one copy, it might happen that optimal solutions are cut off. 66 #define SCIP_DECL_CONSHDLRCOPY(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_Bool* valid) 68 /** destructor of constraint handler to free constraint handler data (called when SCIP is exiting) 84 #define SCIP_DECL_CONSINIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 94 #define SCIP_DECL_CONSEXIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 96 /** presolving initialization method of constraint handler (called when presolving is about to begin) 98 * This method is called when the presolving process is about to begin, even if presolving is turned off. 101 * Necessary modifications that have to be performed even if presolving is turned off should be done here or in the 104 * @note Note that the constraint array might contain constraints that were created but not added to the problem. 105 * Constraints that are not added, i.e., for which SCIPconsIsAdded() returns FALSE, cannot be used for problem 114 #define SCIP_DECL_CONSINITPRE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 116 /** presolving deinitialization method of constraint handler (called after presolving has been finished) 118 * This method is called after the presolving has been finished, even if presolving is turned off. 121 * Necessary modifications that have to be performed even if presolving is turned off should be done here or in the 124 * Besides necessary modifications and clean up, no time consuming operations should be performed, especially if the 125 * problem has already been solved. Use the method SCIPgetStatus(), which in this case returns SCIP_STATUS_OPTIMAL, 128 * @note Note that the constraint array might contain constraints that were created but not added to the problem. 129 * Constraints that are not added, i.e., for which SCIPconsIsAdded() returns FALSE, cannot be used for problem 138 #define SCIP_DECL_CONSEXITPRE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 140 /** solving process initialization method of constraint handler (called when branch and bound process is about to begin) 142 * This method is called when the presolving was finished and the branch and bound process is about to begin. 145 * Besides necessary modifications and clean up, no time consuming operations should be performed, especially if the 146 * problem has already been solved. Use the method SCIPgetStatus(), which in this case returns SCIP_STATUS_OPTIMAL, 149 * @note Note that the constraint array might contain constraints that were created but not added to the problem. 150 * Constraints that are not added, i.e., for which SCIPconsIsAdded() returns FALSE, cannot be used for problem 159 #define SCIP_DECL_CONSINITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 161 /** solving process deinitialization method of constraint handler (called before branch and bound process data is freed) 164 * The constraint handler should use this call to clean up its branch and bound data, in particular to release 174 #define SCIP_DECL_CONSEXITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, SCIP_Bool restart) 178 * @warning There may exist unprocessed events. For example, a variable's bound may have been already changed, but the 187 #define SCIP_DECL_CONSDELETE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, SCIP_CONSDATA** consdata) 197 #define SCIP_DECL_CONSTRANS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* sourcecons, SCIP_CONS** targetcons) 199 /** LP initialization method of constraint handler (called before the initial LP relaxation at a node is solved) 201 * Puts the LP relaxations of all "initial" constraints into the LP. The method should put a canonic LP relaxation 210 #define SCIP_DECL_CONSINITLP(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 214 * Separates all constraints of the constraint handler. The method is called in the LP solution loop, 217 * The first nusefulconss constraints are the ones, that are identified to likely be violated. The separation 218 * method should process only the useful constraints in most runs, and only occasionally the remaining 229 * possible return values for *result (if more than one applies, the first in the list should be used): 234 * - SCIP_NEWROUND : a cutting plane was generated and a new separation round should immediately start 235 * - SCIP_DIDNOTFIND : the separator searched, but did not find domain reductions, cutting planes, or cut constraints 239 #define SCIP_DECL_CONSSEPALP(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, \ 244 * Separates all constraints of the constraint handler. The method is called outside the LP solution loop (e.g., by 248 * The first nusefulconss constraints are the ones, that are identified to likely be violated. The separation 249 * method should process only the useful constraints in most runs, and only occasionally the remaining 261 * possible return values for *result (if more than one applies, the first in the list should be used): 266 * - SCIP_NEWROUND : a cutting plane was generated and a new separation round should immediately start 267 * - SCIP_DIDNOTFIND : the separator searched, but did not find domain reductions, cutting planes, or cut constraints 271 #define SCIP_DECL_CONSSEPASOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, \ 276 * The method is called at the end of the node processing loop for a node where the LP was solved. 277 * The LP solution has to be checked for feasibility. If possible, an infeasibility should be resolved by 278 * branching, reducing a variable's domain to exclude the solution or separating the solution with a valid 281 * The enforcing methods of the active constraint handlers are called in decreasing order of their enforcing 282 * priorities until the first constraint handler returned with the value SCIP_CUTOFF, SCIP_SEPARATED, 284 * The integrality constraint handler has an enforcing priority of zero. A constraint handler which can 285 * (or wants) to enforce its constraints only for integral solutions should have a negative enforcing priority 287 * A constraint handler which wants to incorporate its own branching strategy even on non-integral 288 * solutions must have an enforcing priority greater than zero (e.g. the SOS-constraint incorporates 291 * The first nusefulconss constraints are the ones, that are identified to likely be violated. The enforcing 292 * method should process the useful constraints first. The other nconss - nusefulconss constraints should only 304 * possible return values for *result (if more than one applies, the first in the list should be used): 309 * - SCIP_BRANCHED : no changes were made to the problem, but a branching was applied to resolve an infeasibility 313 #define SCIP_DECL_CONSENFOLP(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, int nusefulconss, \ 318 * The method is called at the end of the node processing loop for a node where the LP was not solved. 319 * The pseudo solution has to be checked for feasibility. If possible, an infeasibility should be resolved by 320 * branching, reducing a variable's domain to exclude the solution or adding an additional constraint. 321 * Separation is not possible, since the LP is not processed at the current node. All LP informations like 324 * Like in the enforcing method for LP solutions, the enforcing methods of the active constraint handlers are 325 * called in decreasing order of their enforcing priorities until the first constraint handler returned with 328 * The first nusefulconss constraints are the ones, that are identified to likely be violated. The enforcing 329 * method should process the useful constraints first. The other nconss - nusefulconss constraints should only 332 * If the pseudo solution's objective value is lower than the lower bound of the node, it cannot be feasible 333 * and the enforcing method may skip it's check and set *result to SCIP_DIDNOTRUN. However, it can also process 346 * possible return values for *result (if more than one applies, the first in the list should be used): 350 * - SCIP_BRANCHED : no changes were made to the problem, but a branching was applied to resolve an infeasibility 351 * - SCIP_SOLVELP : at least one constraint is infeasible, and this can only be resolved by solving the LP 356 #define SCIP_DECL_CONSENFOPS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, int nusefulconss, \ 363 * The check methods of the active constraint handlers are called in decreasing order of their check 365 * The integrality constraint handler has a check priority of zero. A constraint handler which can 366 * (or wants) to check its constraints only for integral solutions should have a negative check priority 368 * A constraint handler which wants to check feasibility even on non-integral solutions must have a 369 * check priority greater than zero (e.g. if the check is much faster than testing all variables for 372 * In some cases, integrality conditions or rows of the current LP don't have to be checked, because their 391 #define SCIP_DECL_CONSCHECK(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, SCIP_SOL* sol, \ 396 * The first nusefulconss constraints are the ones, that are identified to likely be violated. The propagation 397 * method should process only the useful constraints in most runs, and only occasionally the remaining 400 * @note if the constraint handler uses dual information in propagation it is nesassary to check via calling 401 * SCIPallowDualReds and SCIPallowObjProp if dual reductions and propgation with the current cutoff bound, resp., 421 #define SCIP_DECL_CONSPROP(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, int nusefulconss, int nmarkedconss, \ 438 * - nnewchgvartypes : number of variable type changes since the last call to the presolving method 439 * - nnewchgbds : number of variable bounds tightened since the last call to the presolving method 445 * - nnewchgsides : number of changed left or right hand sides since the last call to the presolving method 447 * @note the counters state the changes since the last call including the changes of this presolving method during its 450 * @note if the constraint handler performs dual presolving it is nesassary to check via calling SCIPallowDualReds 463 * - nchgsides : pointer to count total number of changed left/right hand sides of all presolvers 472 * - SCIP_UNBOUNDED : at least one variable is not bounded by any constraint in obj. direction -> problem is unbounded 473 * - SCIP_CUTOFF : at least one constraint is infeasible in the variable's bounds -> problem is infeasible 479 #define SCIP_DECL_CONSPRESOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss, int nrounds, \ 480 SCIP_PRESOLTIMING presoltiming, int nnewfixedvars, int nnewaggrvars, int nnewchgvartypes, int nnewchgbds, int nnewholes, \ 483 int* ndelconss, int* naddconss, int* nupgdconss, int* nchgcoefs, int* nchgsides, SCIP_RESULT* result) 487 * This method is called during conflict analysis. If the constraint handler wants to support conflict analysis, 488 * it should call SCIPinferVarLbCons() or SCIPinferVarUbCons() in domain propagation instead of SCIPchgVarLb() or 490 * In the SCIPinferVarLbCons() and SCIPinferVarUbCons() calls, the handler provides the constraint, that deduced the 492 * The propagation conflict resolving method can then be implemented, to provide a "reasons" for the bound 493 * changes, i.e. the bounds of variables at the time of the propagation, that forced the constraint to set the 494 * conflict variable's bound to its current value. It can use the "inferinfo" tag to identify its own propagation 495 * rule and thus identify the "reason" bounds. The bounds that form the reason of the assignment must then be provided 496 * by calls to SCIPaddConflictLb(), SCIPaddConflictUb(), SCIPaddConflictBd(), SCIPaddConflictRelaxedLb(), 497 * SCIPaddConflictRelaxedUb(), SCIPaddConflictRelaxedBd(), and/or SCIPaddConflictBinvar() in the propagation conflict 500 * For example, the logicor constraint c = "x or y or z" fixes variable z to TRUE (i.e. changes the lower bound of z 501 * to 1.0), if both, x and y, are assigned to FALSE (i.e. if the upper bounds of these variables are 0.0). It uses 502 * SCIPinferVarLbCons(scip, z, 1.0, c, 0) to apply this assignment (an inference information tag is not needed by the 504 * In the conflict analysis, the constraint handler may be asked to resolve the lower bound change on z with 506 * With a call to SCIPvarGetLbAtIndex(z, bdchgidx, TRUE), the handler can find out, that the lower bound of 507 * variable z was set to 1.0 at the given point of time, and should call SCIPaddConflictUb(scip, x, bdchgidx) and 508 * SCIPaddConflictUb(scip, y, bdchgidx) to tell SCIP, that the upper bounds of x and y at this point of time were 516 * - inferinfo : the user information passed to the corresponding SCIPinferVarLbCons() or SCIPinferVarUbCons() call 518 * - bdchgidx : the index of the bound change, representing the point of time where the change took place 525 * - SCIP_SUCCESS : the conflicting bound change has been successfully resolved by adding all reason bounds 526 * - SCIP_DIDNOTFIND : the conflicting bound change could not be resolved and has to be put into the conflict set 530 #define SCIP_DECL_CONSRESPROP(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, \ 531 SCIP_VAR* infervar, int inferinfo, SCIP_BOUNDTYPE boundtype, SCIP_BDCHGIDX* bdchgidx, SCIP_Real relaxedbd, \ 537 * It should update the rounding locks of all associated variables with calls to SCIPaddVarLocks(), 540 * SCIPaddVarLocks(scip, var, nlockspos, nlocksneg), saying that rounding down is potentially rendering the 541 * (positive) constraint infeasible and rounding up is potentially rendering the negation of the constraint 544 * SCIPaddVarLocks(scip, var, nlocksneg, nlockspos), saying that rounding up is potentially rendering the 545 * constraint's negation infeasible and rounding up is potentially rendering the constraint itself 547 * - If the constraint may get violated by changing the variable in any direction, it should call 550 * Consider the linear constraint "3x -5y +2z <= 7" as an example. The variable rounding lock method of the 552 * SCIPaddVarLocks(scip, y, nlockspos, nlocksneg) and SCIPaddVarLocks(scip, z, nlocksneg, nlockspos) to tell SCIP, 553 * that rounding up of x and z and rounding down of y can destroy the feasibility of the constraint, while rounding 554 * down of x and z and rounding up of y can destroy the feasibility of the constraint's negation "3x -5y +2z > 7". 556 * SCIPaddVarLocks(scip, ..., nlockspos + nlocksneg, nlockspos + nlocksneg) on all variables, since rounding in both 557 * directions of each variable can destroy both the feasibility of the constraint and it's negation 560 * If the constraint itself contains other constraints as sub constraints (e.g. the "or" constraint concatenation 561 * "c(x) or d(x)"), the rounding lock methods of these constraints should be called in a proper way. 563 * SCIPaddConsLocks(scip, c, nlockspos, nlocksneg), saying that infeasibility of c may lead to infeasibility of 564 * the (positive) constraint, and infeasibility of c's negation (i.e. feasibility of c) may lead to infeasibility 566 * - If the constraint may get violated by the feasibility of the sub constraint c, it should call 567 * SCIPaddConsLocks(scip, c, nlocksneg, nlockspos), saying that infeasibility of c may lead to infeasibility of 568 * the constraint's negation (i.e. feasibility of the constraint), and infeasibility of c's negation (i.e. feasibility 570 * - If the constraint may get violated by any change in the feasibility of the sub constraint c, it should call 573 * Consider the or concatenation "c(x) or d(x)". The variable rounding lock method of the or constraint handler 574 * should call SCIPaddConsLocks(scip, c, nlockspos, nlocksneg) and SCIPaddConsLocks(scip, d, nlockspos, nlocksneg) 577 * As a second example, consider the equivalence constraint "y <-> c(x)" with variable y and constraint c. The 578 * constraint demands, that y == 1 if and only if c(x) is satisfied. The variable lock method of the corresponding 579 * constraint handler should call SCIPaddVarLocks(scip, y, nlockspos + nlocksneg, nlockspos + nlocksneg) and 580 * SCIPaddConsLocks(scip, c, nlockspos + nlocksneg, nlockspos + nlocksneg), because any modification to the 581 * value of y or to the feasibility of c can alter the feasibility of the equivalence constraint. 586 * - cons : the constraint that should lock rounding of its variables, or NULL if the constraint handler 588 * - nlockspos : number of times, the roundings should be locked for the constraint (may be negative) 589 * - nlocksneg : number of times, the roundings should be locked for the constraint's negation (may be negative) 591 #define SCIP_DECL_CONSLOCK(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, int nlockspos, int nlocksneg) 595 * WARNING! There may exist unprocessed events. For example, a variable's bound may have been already changed, but 598 * This method is always called after a constraint of the constraint handler was activated. The constraint 606 #define SCIP_DECL_CONSACTIVE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons) 610 * WARNING! There may exist unprocessed events. For example, a variable's bound may have been already changed, but 613 * This method is always called before a constraint of the constraint handler is deactivated. The constraint 621 #define SCIP_DECL_CONSDEACTIVE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons) 625 * WARNING! There may exist unprocessed events. For example, a variable's bound may have been already changed, but 628 * This method is always called after a constraint of the constraint handler was enabled. The constraint 636 #define SCIP_DECL_CONSENABLE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons) 640 * WARNING! There may exist unprocessed events. For example, a variable's bound may have been already changed, but 643 * This method is always called before a constraint of the constraint handler is disabled. The constraint 651 #define SCIP_DECL_CONSDISABLE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons) 655 * This method is optinal and only of interest if you are using SCIP as a branch-and-price framework. That means, you 656 * are generating new variables during the search. If you are not doing that just define the function pointer to be 659 * If this method gets implemented you should iterate over all constraints of the constraint handler and delete all 668 #define SCIP_DECL_CONSDELVARS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** conss, int nconss) 672 * The constraint handler can store a representation of the constraint into the given text file. Use the method 675 * @note There are several methods which help to display variables. These are SCIPwriteVarName(), SCIPwriteVarsList(), 678 * input: - scip : SCIP main data structure - conshdlr : the constraint handler itself - cons : the constraint that 682 #define SCIP_DECL_CONSPRINT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, FILE* file) 686 * The constraint handler can provide a copy method which copies a constraint from one SCIP data structure into a other 687 * SCIP data structure. If a copy of a constraint is created the constraint has to be captured (The capture is usually 690 * If the copy process was a one to one the valid pointer can set to TRUE. Otherwise, you have to set this pointer to 691 * FALSE. In case all problem defining objects (constraint handlers and variable pricers) return a valid TRUE for all 692 * their copying calls, SCIP assumes that it is a overall one to one copy of the original instance. In this case any 693 * reductions made in the copied SCIP instance can be transfer to the original SCIP instance. If the valid pointer is 694 * set to TRUE and it was not one to one copy, it might happen that optimal solutions are cut off. 705 * - varmap : a SCIP_HASHMAP mapping variables of the source SCIP to corresponding variables of the target SCIP 706 * - consmap : a SCIP_HASHMAP mapping constraints of the source SCIP to corresponding constraints of the target SCIP 724 SCIP* sourcescip, SCIP_CONSHDLR* sourceconshdlr, SCIP_CONS* sourcecons, SCIP_HASHMAP* varmap, SCIP_HASHMAP* consmap, \ 725 SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, \ 726 SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode, \ 731 * The constraint handler can provide a callback to parse the output created by the display method 734 * @note For parsing there are several methods which are handy. Have a look at: SCIPparseVarName(), 735 * SCIPparseVarsList(), SCIPparseVarsLinearsum(), SCIPparseVarsPolynomial(), SCIPstrToRealValue(), and 758 #define SCIP_DECL_CONSPARSE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS** cons, \ 760 SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, \ 761 SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode, SCIP_Bool* success) 765 * The constraint handler can (this callback is optional) provide this callback to return the variables which are 766 * involved in that particular constraint. If this is possible, the variables should be copyied into the variables 767 * array and the success pointers has to be set to TRUE. Otherwise the success has to be set FALSE or the callback 777 * - varssize : available slots in vars array which is needed to check if the array is large enough 780 #define SCIP_DECL_CONSGETVARS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, \ 785 * The constraint handler can (this callback is optional) provide this callback to return the number variable which are 786 * involved in that particular constraint. If this is not possible, the success pointers has to be set to FALSE or the 796 * - success : pointer to store whether the constraint successfully returned the number of variables 798 #define SCIP_DECL_CONSGETNVARS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_CONS* cons, \ 803 * This callback is used inside the various diving heuristics of SCIP and does not affect the normal branching 805 * The constraint handler can provide this callback to render the current solution (even more) infeasible by 807 * since diving heuristics do not necessarily solve LP relaxations at every probing depth, some of the variable 809 * The solution is rendered infeasible by determining bound changes that should be applied to the next explored search node 811 * An alternative in case that the preferred bound change(s) were detected infeasible must be provided. 813 * The constraint handler must take care to only add bound changes that further shrink the variable domain. 815 * The success pointer must be used to indicate whether the constraint handler succeeded in selecting diving bound 816 * changes. The infeasible pointer should be set to TRUE if the constraint handler found a local infeasibility. If the 817 * constraint handler needs to select between several candidates, it may use the scoring mechanism of the diveset 824 * @note: @p sol is usually the LP relaxation solution unless the caller of the method, usually a diving heuristic, 834 * - success : pointer to store whether the constraint handler succeeded to determine dive bound changes 835 * - infeasible : pointer to store whether the constraint handler detected an infeasibility in the local node 837 #define SCIP_DECL_CONSGETDIVEBDCHGS(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONSHDLR* conshdlr, SCIP_DIVESET* diveset, \
timing definitions for SCIP type definitions for return codes for SCIP methods type definitions for primal heuristics type definitions for SCIP's main datastructure type definitions for problem variables type definitions for storing primal CIP solutions result codes for SCIP callback methods common defines and data types used in all packages of SCIP |