1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 2 /* */ 3 /* This file is part of the program and library */ 4 /* SCIP --- Solving Constraint Integer Programs */ 5 /* */ 6 /* Copyright (C) 2002-2021 Konrad-Zuse-Zentrum */ 7 /* fuer Informationstechnik Berlin */ 8 /* */ 9 /* SCIP is distributed under the terms of the ZIB Academic License. */ 10 /* */ 11 /* You should have received a copy of the ZIB Academic License */ 12 /* along with SCIP; see the file COPYING. If not visit scipopt.org. */ 13 /* */ 14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 15 16 /**@file cons_linear.h 17 * @ingroup CONSHDLRS 18 * @brief Constraint handler for linear constraints in their most general form, \f$lhs <= a^T x <= rhs\f$. 19 * @author Tobias Achterberg 20 * @author Timo Berthold 21 * @author Marc Pfetsch 22 * @author Kati Wolter 23 * 24 */ 25 26 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 27 28 #ifndef __SCIP_CONS_LINEAR_H__ 29 #define __SCIP_CONS_LINEAR_H__ 30 31 #include "scip/def.h" 32 #include "scip/type_cons.h" 33 #include "scip/type_lp.h" 34 #include "scip/type_misc.h" 35 #include "scip/type_retcode.h" 36 #include "scip/type_scip.h" 37 #include "scip/type_sol.h" 38 #include "scip/type_var.h" 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 45 46 /* 47 * constraint specific interface methods 48 */ 49 50 /** creates the handler for linear constraints and includes it in SCIP 51 * 52 * @ingroup ConshdlrIncludes 53 * */ 54 SCIP_EXPORT 55 SCIP_RETCODE SCIPincludeConshdlrLinear( 56 SCIP* scip /**< SCIP data structure */ 57 ); 58 59 /**@addtogroup CONSHDLRS 60 * 61 * @{ 62 * 63 * @name Linear Constraints 64 * 65 * This constraint handler handles linear constraints in their most general form. That is, 66 * \f[ 67 * lhs \leq \sum_{i=1}^n a_i x_i \leq rhs 68 * \f] 69 * with \f$a_i \in Q, i = 1,\dots,n\f$, \f$lhs\in Q \cup \{-\infty\}\f$, \f$rhs\in Q \cup \{\infty\}\f$, 70 * and decision variables \f$x_i, i = 1,\dots,n\f$ which can be binary, integer, or continuous. 71 * 72 * Furthermore, this header offers the upgrade functionality of a general linear constraint into a more specific 73 * constraint, such as a knapsack constraint, via SCIP_DECL_LINCONSUPGD() and SCIPincludeLinconsUpgrade() 74 * 75 * @{ 76 */ 77 78 typedef struct SCIP_LinConsUpgrade SCIP_LINCONSUPGRADE; /**< linear constraint update method */ 79 80 /** upgrading method for linear constraints into more specific constraints 81 * 82 * input: 83 * - scip : SCIP main data structure 84 * - cons : the linear constraint to upgrade 85 * - nvars : number of variables in the constraint 86 * - vars : array with constraint variables 87 * - vals : array with constraint coefficients 88 * - lhs : left hand side of linear constraint 89 * - rhs : right hand side of linear constraint 90 * - nposbin : number of binary variables with positive coefficient 91 * - nnegbin : number of binary variables with negative coefficient 92 * - nposint : number of integer variables with positive coefficient 93 * - nnegint : number of integer variables with negative coefficient 94 * - nposimpl : number of implicit integer variables with positive coefficient (including implicit binary variables) 95 * - nnegimpl : number of implicit integer variables with negative coefficient (including implicit binary variables) 96 * - nposimplbin : number of implicit binary variables with positive coefficient 97 * - nnegimplbin : number of implicit binary variables with negative coefficient 98 * - nposcont : number of continuous variables with positive coefficient 99 * - nnegcont : number of continuous variables with negative coefficient 100 * - ncoeffspone : number of +1 coefficients 101 * - ncoeffsnone : number of -1 coefficients 102 * - ncoeffspint : number of positive integral coefficients other than +1 103 * - ncoeffsnint : number of negative integral coefficients other than -1 104 * - ncoeffspfrac : number of positive fractional coefficients 105 * - ncoeffsnfrac : number of negative fractional coefficients 106 * - poscoeffsum : sum of all positive coefficients 107 * - negcoeffsum : sum of all negative coefficients 108 * - integral : TRUE iff constraints activity value is always integral 109 * - upgdcons : pointer to store the upgraded constraint 110 */ 111 #define SCIP_DECL_LINCONSUPGD(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONS* cons, int nvars, SCIP_VAR** vars, SCIP_Real* vals, SCIP_Real lhs, SCIP_Real rhs, \ 112 int nposbin, int nnegbin, int nposint, int nnegint, int nposimpl, int nnegimpl, int nposimplbin, int nnegimplbin, int nposcont, int nnegcont, \ 113 int ncoeffspone, int ncoeffsnone, int ncoeffspint, int ncoeffsnint, int ncoeffspfrac, int ncoeffsnfrac, \ 114 SCIP_Real poscoeffsum, SCIP_Real negcoeffsum, SCIP_Bool integral, SCIP_CONS** upgdcons) 115 116 /** includes a linear constraint update method into the linear constraint handler */ 117 SCIP_EXPORT 118 SCIP_RETCODE SCIPincludeLinconsUpgrade( 119 SCIP* scip, /**< SCIP data structure */ 120 SCIP_DECL_LINCONSUPGD((*linconsupgd)), /**< method to call for upgrading linear constraint */ 121 int priority, /**< priority of upgrading method */ 122 const char* conshdlrname /**< name of the constraint handler */ 123 ); 124 125 /** creates and captures a linear constraint 126 * 127 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 128 */ 129 SCIP_EXPORT 130 SCIP_RETCODE SCIPcreateConsLinear( 131 SCIP* scip, /**< SCIP data structure */ 132 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 133 const char* name, /**< name of constraint */ 134 int nvars, /**< number of nonzeros in the constraint */ 135 SCIP_VAR** vars, /**< array with variables of constraint entries */ 136 SCIP_Real* vals, /**< array with coefficients of constraint entries */ 137 SCIP_Real lhs, /**< left hand side of constraint */ 138 SCIP_Real rhs, /**< right hand side of constraint */ 139 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 140 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 141 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 142 * Usually set to TRUE. */ 143 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 144 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 145 SCIP_Bool check, /**< should the constraint be checked for feasibility? 146 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 147 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 148 * Usually set to TRUE. */ 149 SCIP_Bool local, /**< is constraint only valid locally? 150 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 151 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? 152 * Usually set to FALSE. In column generation applications, set to TRUE if pricing 153 * adds coefficients to this constraint. */ 154 SCIP_Bool dynamic, /**< is constraint subject to aging? 155 * Usually set to FALSE. Set to TRUE for own cuts which 156 * are separated as constraints. */ 157 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 158 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 159 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 160 * if it may be moved to a more global node? 161 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 162 ); 163 164 /** creates and captures a linear constraint 165 * in its most basic version, i. e., all constraint flags are set to their basic value as explained for the 166 * method SCIPcreateConsLinear(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h 167 * 168 * @see SCIPcreateConsLinear() for information about the basic constraint flag configuration 169 * 170 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 171 */ 172 SCIP_EXPORT 173 SCIP_RETCODE SCIPcreateConsBasicLinear( 174 SCIP* scip, /**< SCIP data structure */ 175 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 176 const char* name, /**< name of constraint */ 177 int nvars, /**< number of nonzeros in the constraint */ 178 SCIP_VAR** vars, /**< array with variables of constraint entries */ 179 SCIP_Real* vals, /**< array with coefficients of constraint entries */ 180 SCIP_Real lhs, /**< left hand side of constraint */ 181 SCIP_Real rhs /**< right hand side of constraint */ 182 ); 183 184 /** creates by copying and captures a linear constraint */ 185 SCIP_EXPORT 186 SCIP_RETCODE SCIPcopyConsLinear( 187 SCIP* scip, /**< target SCIP data structure */ 188 SCIP_CONS** cons, /**< pointer to store the created target constraint */ 189 SCIP* sourcescip, /**< source SCIP data structure */ 190 const char* name, /**< name of constraint */ 191 int nvars, /**< number of variables in source variable array */ 192 SCIP_VAR** sourcevars, /**< source variables of the linear constraints */ 193 SCIP_Real* sourcecoefs, /**< coefficient array of the linear constraint, or NULL if all coefficients are one */ 194 SCIP_Real lhs, /**< left hand side of the linear constraint */ 195 SCIP_Real rhs, /**< right hand side of the linear constraint */ 196 SCIP_HASHMAP* varmap, /**< a SCIP_HASHMAP mapping variables of the source SCIP to corresponding 197 * variables of the target SCIP */ 198 SCIP_HASHMAP* consmap, /**< a hashmap to store the mapping of source constraints to the corresponding 199 * target constraints */ 200 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? */ 201 SCIP_Bool separate, /**< should the constraint be separated during LP processing? */ 202 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? */ 203 SCIP_Bool check, /**< should the constraint be checked for feasibility? */ 204 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? */ 205 SCIP_Bool local, /**< is constraint only valid locally? */ 206 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? */ 207 SCIP_Bool dynamic, /**< is constraint subject to aging? */ 208 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? */ 209 SCIP_Bool stickingatnode, /**< should the constraint always be kept at the node where it was added, even 210 * if it may be moved to a more global node? */ 211 SCIP_Bool global, /**< create a global or a local copy? */ 212 SCIP_Bool* valid /**< pointer to store if the copying was valid */ 213 ); 214 215 /** adds coefficient to linear constraint (if it is not zero) */ 216 SCIP_EXPORT 217 SCIP_RETCODE SCIPaddCoefLinear( 218 SCIP* scip, /**< SCIP data structure */ 219 SCIP_CONS* cons, /**< constraint data */ 220 SCIP_VAR* var, /**< variable of constraint entry */ 221 SCIP_Real val /**< coefficient of constraint entry */ 222 ); 223 224 /** changes coefficient of variable in linear constraint; deletes the variable if coefficient is zero; adds variable if 225 * not yet contained in the constraint 226 * 227 * @note This method may only be called during problem creation stage for an original constraint and variable. 228 * 229 * @note This method requires linear time to search for occurences of the variable in the constraint data. 230 */ 231 SCIP_EXPORT 232 SCIP_RETCODE SCIPchgCoefLinear( 233 SCIP* scip, /**< SCIP data structure */ 234 SCIP_CONS* cons, /**< constraint data */ 235 SCIP_VAR* var, /**< variable of constraint entry */ 236 SCIP_Real val /**< new coefficient of constraint entry */ 237 ); 238 239 /** deletes variable from linear constraint 240 * 241 * @note This method may only be called during problem creation stage for an original constraint and variable. 242 * 243 * @note This method requires linear time to search for occurences of the variable in the constraint data. 244 */ 245 SCIP_EXPORT 246 SCIP_RETCODE SCIPdelCoefLinear( 247 SCIP* scip, /**< SCIP data structure */ 248 SCIP_CONS* cons, /**< constraint data */ 249 SCIP_VAR* var /**< variable of constraint entry */ 250 ); 251 252 /** gets left hand side of linear constraint */ 253 SCIP_EXPORT 254 SCIP_Real SCIPgetLhsLinear( 255 SCIP* scip, /**< SCIP data structure */ 256 SCIP_CONS* cons /**< constraint data */ 257 ); 258 259 /** gets right hand side of linear constraint */ 260 SCIP_EXPORT 261 SCIP_Real SCIPgetRhsLinear( 262 SCIP* scip, /**< SCIP data structure */ 263 SCIP_CONS* cons /**< constraint data */ 264 ); 265 266 /** changes left hand side of linear constraint */ 267 SCIP_EXPORT 268 SCIP_RETCODE SCIPchgLhsLinear( 269 SCIP* scip, /**< SCIP data structure */ 270 SCIP_CONS* cons, /**< constraint data */ 271 SCIP_Real lhs /**< new left hand side */ 272 ); 273 274 /** changes right hand side of linear constraint */ 275 SCIP_EXPORT 276 SCIP_RETCODE SCIPchgRhsLinear( 277 SCIP* scip, /**< SCIP data structure */ 278 SCIP_CONS* cons, /**< constraint data */ 279 SCIP_Real rhs /**< new right hand side */ 280 ); 281 282 /** gets the number of variables in the linear constraint */ 283 SCIP_EXPORT 284 int SCIPgetNVarsLinear( 285 SCIP* scip, /**< SCIP data structure */ 286 SCIP_CONS* cons /**< constraint data */ 287 ); 288 289 /** gets the array of variables in the linear constraint; the user must not modify this array! */ 290 SCIP_EXPORT 291 SCIP_VAR** SCIPgetVarsLinear( 292 SCIP* scip, /**< SCIP data structure */ 293 SCIP_CONS* cons /**< constraint data */ 294 ); 295 296 /** gets the array of coefficient values in the linear constraint; the user must not modify this array! */ 297 SCIP_EXPORT 298 SCIP_Real* SCIPgetValsLinear( 299 SCIP* scip, /**< SCIP data structure */ 300 SCIP_CONS* cons /**< constraint data */ 301 ); 302 303 /** gets the activity of the linear constraint in the given solution 304 * 305 * @note if the solution contains values at infinity, this method will return SCIP_INVALID in case the activity 306 * comprises positive and negative infinity contributions 307 */ 308 SCIP_EXPORT 309 SCIP_Real SCIPgetActivityLinear( 310 SCIP* scip, /**< SCIP data structure */ 311 SCIP_CONS* cons, /**< constraint data */ 312 SCIP_SOL* sol /**< solution, or NULL to use current node's solution */ 313 ); 314 315 /** gets the feasibility of the linear constraint in the given solution */ 316 SCIP_EXPORT 317 SCIP_Real SCIPgetFeasibilityLinear( 318 SCIP* scip, /**< SCIP data structure */ 319 SCIP_CONS* cons, /**< constraint data */ 320 SCIP_SOL* sol /**< solution, or NULL to use current node's solution */ 321 ); 322 323 /** gets the dual solution of the linear constraint in the current LP */ 324 SCIP_EXPORT 325 SCIP_Real SCIPgetDualsolLinear( 326 SCIP* scip, /**< SCIP data structure */ 327 SCIP_CONS* cons /**< constraint data */ 328 ); 329 330 /** gets the dual Farkas value of the linear constraint in the current infeasible LP */ 331 SCIP_EXPORT 332 SCIP_Real SCIPgetDualfarkasLinear( 333 SCIP* scip, /**< SCIP data structure */ 334 SCIP_CONS* cons /**< constraint data */ 335 ); 336 337 /** returns the linear relaxation of the given linear constraint; may return NULL if no LP row was yet created; 338 * the user must not modify the row! 339 */ 340 SCIP_EXPORT 341 SCIP_ROW* SCIPgetRowLinear( 342 SCIP* scip, /**< SCIP data structure */ 343 SCIP_CONS* cons /**< constraint data */ 344 ); 345 346 /** tries to automatically convert a linear constraint into a more specific and more specialized constraint */ 347 SCIP_EXPORT 348 SCIP_RETCODE SCIPupgradeConsLinear( 349 SCIP* scip, /**< SCIP data structure */ 350 SCIP_CONS* cons, /**< source constraint to try to convert */ 351 SCIP_CONS** upgdcons /**< pointer to store upgraded constraint, or NULL if not successful */ 352 ); 353 354 /** performs linear constraint type classification as used for MIPLIB 355 * 356 * iterates through all linear constraints and stores relevant statistics in the linear constraint statistics \p linconsstats. 357 * 358 * @note only constraints are iterated that belong to the linear constraint handler. If the problem has been presolved already, 359 * constraints that were upgraded to more special types such as, e.g., varbound constraints, will not be shown correctly anymore. 360 * Similarly, if specialized constraints were created through the API, these are currently not present. 361 */ 362 SCIP_EXPORT 363 SCIP_RETCODE SCIPclassifyConstraintTypesLinear( 364 SCIP* scip, /**< SCIP data structure */ 365 SCIP_LINCONSSTATS* linconsstats /**< linear constraint type classification */ 366 ); 367 368 369 /** cleans up (multi-)aggregations and fixings from linear constraints */ 370 SCIP_EXPORT 371 SCIP_RETCODE SCIPcleanupConssLinear( 372 SCIP* scip, /**< SCIP data structure */ 373 SCIP_Bool onlychecked, /**< should only checked constraints be cleaned up? */ 374 SCIP_Bool* infeasible /**< pointer to return whether the problem was detected to be infeasible */ 375 ); 376 377 /** @} */ 378 379 /** @} */ 380 381 #ifdef __cplusplus 382 } 383 #endif 384 385 #endif 386