1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 2 /* */ 3 /* This file is part of the program and library */ 4 /* SCIP --- Solving Constraint Integer Programs */ 5 /* */ 6 /* Copyright (c) 2002-2023 Zuse Institute Berlin (ZIB) */ 7 /* */ 8 /* Licensed under the Apache License, Version 2.0 (the "License"); */ 9 /* you may not use this file except in compliance with the License. */ 10 /* You may obtain a copy of the License at */ 11 /* */ 12 /* http://www.apache.org/licenses/LICENSE-2.0 */ 13 /* */ 14 /* Unless required by applicable law or agreed to in writing, software */ 15 /* distributed under the License is distributed on an "AS IS" BASIS, */ 16 /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */ 17 /* See the License for the specific language governing permissions and */ 18 /* limitations under the License. */ 19 /* */ 20 /* You should have received a copy of the Apache-2.0 license */ 21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */ 22 /* */ 23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 24 25 /**@file cons_linear.h 26 * @ingroup CONSHDLRS 27 * @brief Constraint handler for linear constraints in their most general form, \f$lhs <= a^T x <= rhs\f$. 28 * @author Tobias Achterberg 29 * @author Timo Berthold 30 * @author Marc Pfetsch 31 * @author Kati Wolter 32 * 33 */ 34 35 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 36 37 #ifndef __SCIP_CONS_LINEAR_H__ 38 #define __SCIP_CONS_LINEAR_H__ 39 40 #include "scip/def.h" 41 #include "scip/type_cons.h" 42 #include "scip/type_lp.h" 43 #include "scip/type_misc.h" 44 #include "scip/type_retcode.h" 45 #include "scip/type_scip.h" 46 #include "scip/type_sol.h" 47 #include "scip/type_var.h" 48 49 #ifdef __cplusplus 50 extern "C" { 51 #endif 52 53 54 55 /* 56 * constraint specific interface methods 57 */ 58 59 /** creates the handler for linear constraints and includes it in SCIP 60 * 61 * @ingroup ConshdlrIncludes 62 * */ 63 SCIP_EXPORT 64 SCIP_RETCODE SCIPincludeConshdlrLinear( 65 SCIP* scip /**< SCIP data structure */ 66 ); 67 68 /**@addtogroup CONSHDLRS 69 * 70 * @{ 71 * 72 * @name Linear Constraints 73 * 74 * This constraint handler handles linear constraints in their most general form. That is, 75 * \f[ 76 * lhs \leq \sum_{i=1}^n a_i x_i \leq rhs 77 * \f] 78 * with \f$a_i \in Q, i = 1,\dots,n\f$, \f$lhs\in Q \cup \{-\infty\}\f$, \f$rhs\in Q \cup \{\infty\}\f$, 79 * and decision variables \f$x_i, i = 1,\dots,n\f$ which can be binary, integer, or continuous. 80 * 81 * Furthermore, this header offers the upgrade functionality of a general linear constraint into a more specific 82 * constraint, such as a knapsack constraint, via SCIP_DECL_LINCONSUPGD() and SCIPincludeLinconsUpgrade() 83 * 84 * @{ 85 */ 86 87 typedef struct SCIP_LinConsUpgrade SCIP_LINCONSUPGRADE; /**< linear constraint update method */ 88 89 /** upgrading method for linear constraints into more specific constraints 90 * 91 * input: 92 * - scip : SCIP main data structure 93 * - cons : the linear constraint to upgrade 94 * - nvars : number of variables in the constraint 95 * - vars : array with constraint variables 96 * - vals : array with constraint coefficients 97 * - lhs : left hand side of linear constraint 98 * - rhs : right hand side of linear constraint 99 * - nposbin : number of binary variables with positive coefficient 100 * - nnegbin : number of binary variables with negative coefficient 101 * - nposint : number of integer variables with positive coefficient 102 * - nnegint : number of integer variables with negative coefficient 103 * - nposimpl : number of implicit integer variables with positive coefficient (including implicit binary variables) 104 * - nnegimpl : number of implicit integer variables with negative coefficient (including implicit binary variables) 105 * - nposimplbin : number of implicit binary variables with positive coefficient 106 * - nnegimplbin : number of implicit binary variables with negative coefficient 107 * - nposcont : number of continuous variables with positive coefficient 108 * - nnegcont : number of continuous variables with negative coefficient 109 * - ncoeffspone : number of +1 coefficients 110 * - ncoeffsnone : number of -1 coefficients 111 * - ncoeffspint : number of positive integral coefficients other than +1 112 * - ncoeffsnint : number of negative integral coefficients other than -1 113 * - ncoeffspfrac : number of positive fractional coefficients 114 * - ncoeffsnfrac : number of negative fractional coefficients 115 * - poscoeffsum : sum of all positive coefficients 116 * - negcoeffsum : sum of all negative coefficients 117 * - integral : TRUE iff constraints activity value is always integral 118 * - upgdcons : pointer to store the upgraded constraint 119 */ 120 #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, \ 121 int nposbin, int nnegbin, int nposint, int nnegint, int nposimpl, int nnegimpl, int nposimplbin, int nnegimplbin, int nposcont, int nnegcont, \ 122 int ncoeffspone, int ncoeffsnone, int ncoeffspint, int ncoeffsnint, int ncoeffspfrac, int ncoeffsnfrac, \ 123 SCIP_Real poscoeffsum, SCIP_Real negcoeffsum, SCIP_Bool integral, SCIP_CONS** upgdcons) 124 125 /** includes a linear constraint update method into the linear constraint handler */ 126 SCIP_EXPORT 127 SCIP_RETCODE SCIPincludeLinconsUpgrade( 128 SCIP* scip, /**< SCIP data structure */ 129 SCIP_DECL_LINCONSUPGD((*linconsupgd)), /**< method to call for upgrading linear constraint */ 130 int priority, /**< priority of upgrading method */ 131 const char* conshdlrname /**< name of the constraint handler */ 132 ); 133 134 /** creates and captures a linear constraint 135 * 136 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 137 */ 138 SCIP_EXPORT 139 SCIP_RETCODE SCIPcreateConsLinear( 140 SCIP* scip, /**< SCIP data structure */ 141 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 142 const char* name, /**< name of constraint */ 143 int nvars, /**< number of nonzeros in the constraint */ 144 SCIP_VAR** vars, /**< array with variables of constraint entries */ 145 SCIP_Real* vals, /**< array with coefficients of constraint entries */ 146 SCIP_Real lhs, /**< left hand side of constraint */ 147 SCIP_Real rhs, /**< right hand side of constraint */ 148 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 149 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 150 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 151 * Usually set to TRUE. */ 152 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 153 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 154 SCIP_Bool check, /**< should the constraint be checked for feasibility? 155 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 156 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 157 * Usually set to TRUE. */ 158 SCIP_Bool local, /**< is constraint only valid locally? 159 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 160 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? 161 * Usually set to FALSE. In column generation applications, set to TRUE if pricing 162 * adds coefficients to this constraint. */ 163 SCIP_Bool dynamic, /**< is constraint subject to aging? 164 * Usually set to FALSE. Set to TRUE for own cuts which 165 * are separated as constraints. */ 166 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 167 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 168 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 169 * if it may be moved to a more global node? 170 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 171 ); 172 173 /** creates and captures a linear constraint 174 * in its most basic version, i. e., all constraint flags are set to their basic value as explained for the 175 * method SCIPcreateConsLinear(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h 176 * 177 * @see SCIPcreateConsLinear() for information about the basic constraint flag configuration 178 * 179 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 180 */ 181 SCIP_EXPORT 182 SCIP_RETCODE SCIPcreateConsBasicLinear( 183 SCIP* scip, /**< SCIP data structure */ 184 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 185 const char* name, /**< name of constraint */ 186 int nvars, /**< number of nonzeros in the constraint */ 187 SCIP_VAR** vars, /**< array with variables of constraint entries */ 188 SCIP_Real* vals, /**< array with coefficients of constraint entries */ 189 SCIP_Real lhs, /**< left hand side of constraint */ 190 SCIP_Real rhs /**< right hand side of constraint */ 191 ); 192 193 /** creates by copying and captures a linear constraint */ 194 SCIP_EXPORT 195 SCIP_RETCODE SCIPcopyConsLinear( 196 SCIP* scip, /**< target SCIP data structure */ 197 SCIP_CONS** cons, /**< pointer to store the created target constraint */ 198 SCIP* sourcescip, /**< source SCIP data structure */ 199 const char* name, /**< name of constraint */ 200 int nvars, /**< number of variables in source variable array */ 201 SCIP_VAR** sourcevars, /**< source variables of the linear constraints */ 202 SCIP_Real* sourcecoefs, /**< coefficient array of the linear constraint, or NULL if all coefficients are one */ 203 SCIP_Real lhs, /**< left hand side of the linear constraint */ 204 SCIP_Real rhs, /**< right hand side of the linear constraint */ 205 SCIP_HASHMAP* varmap, /**< a SCIP_HASHMAP mapping variables of the source SCIP to corresponding 206 * variables of the target SCIP */ 207 SCIP_HASHMAP* consmap, /**< a hashmap to store the mapping of source constraints to the corresponding 208 * target constraints */ 209 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? */ 210 SCIP_Bool separate, /**< should the constraint be separated during LP processing? */ 211 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? */ 212 SCIP_Bool check, /**< should the constraint be checked for feasibility? */ 213 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? */ 214 SCIP_Bool local, /**< is constraint only valid locally? */ 215 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? */ 216 SCIP_Bool dynamic, /**< is constraint subject to aging? */ 217 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? */ 218 SCIP_Bool stickingatnode, /**< should the constraint always be kept at the node where it was added, even 219 * if it may be moved to a more global node? */ 220 SCIP_Bool global, /**< create a global or a local copy? */ 221 SCIP_Bool* valid /**< pointer to store if the copying was valid */ 222 ); 223 224 /** adds coefficient to linear constraint (if it is not zero) */ 225 SCIP_EXPORT 226 SCIP_RETCODE SCIPaddCoefLinear( 227 SCIP* scip, /**< SCIP data structure */ 228 SCIP_CONS* cons, /**< constraint data */ 229 SCIP_VAR* var, /**< variable of constraint entry */ 230 SCIP_Real val /**< coefficient of constraint entry */ 231 ); 232 233 /** changes coefficient of variable in linear constraint; deletes the variable if coefficient is zero; adds variable if 234 * not yet contained in the constraint 235 * 236 * @note This method may only be called during problem creation stage for an original constraint and variable. 237 * 238 * @note This method requires linear time to search for occurences of the variable in the constraint data. 239 */ 240 SCIP_EXPORT 241 SCIP_RETCODE SCIPchgCoefLinear( 242 SCIP* scip, /**< SCIP data structure */ 243 SCIP_CONS* cons, /**< constraint data */ 244 SCIP_VAR* var, /**< variable of constraint entry */ 245 SCIP_Real val /**< new coefficient of constraint entry */ 246 ); 247 248 /** deletes variable from linear constraint 249 * 250 * @note This method may only be called during problem creation stage for an original constraint and variable. 251 * 252 * @note This method requires linear time to search for occurences of the variable in the constraint data. 253 */ 254 SCIP_EXPORT 255 SCIP_RETCODE SCIPdelCoefLinear( 256 SCIP* scip, /**< SCIP data structure */ 257 SCIP_CONS* cons, /**< constraint data */ 258 SCIP_VAR* var /**< variable of constraint entry */ 259 ); 260 261 /** gets left hand side of linear constraint */ 262 SCIP_EXPORT 263 SCIP_Real SCIPgetLhsLinear( 264 SCIP* scip, /**< SCIP data structure */ 265 SCIP_CONS* cons /**< constraint data */ 266 ); 267 268 /** gets right hand side of linear constraint */ 269 SCIP_EXPORT 270 SCIP_Real SCIPgetRhsLinear( 271 SCIP* scip, /**< SCIP data structure */ 272 SCIP_CONS* cons /**< constraint data */ 273 ); 274 275 /** changes left hand side of linear constraint */ 276 SCIP_EXPORT 277 SCIP_RETCODE SCIPchgLhsLinear( 278 SCIP* scip, /**< SCIP data structure */ 279 SCIP_CONS* cons, /**< constraint data */ 280 SCIP_Real lhs /**< new left hand side */ 281 ); 282 283 /** changes right hand side of linear constraint */ 284 SCIP_EXPORT 285 SCIP_RETCODE SCIPchgRhsLinear( 286 SCIP* scip, /**< SCIP data structure */ 287 SCIP_CONS* cons, /**< constraint data */ 288 SCIP_Real rhs /**< new right hand side */ 289 ); 290 291 /** gets the number of variables in the linear constraint */ 292 SCIP_EXPORT 293 int SCIPgetNVarsLinear( 294 SCIP* scip, /**< SCIP data structure */ 295 SCIP_CONS* cons /**< constraint data */ 296 ); 297 298 /** gets the array of variables in the linear constraint; the user must not modify this array! */ 299 SCIP_EXPORT 300 SCIP_VAR** SCIPgetVarsLinear( 301 SCIP* scip, /**< SCIP data structure */ 302 SCIP_CONS* cons /**< constraint data */ 303 ); 304 305 /** gets the array of coefficient values in the linear constraint; the user must not modify this array! */ 306 SCIP_EXPORT 307 SCIP_Real* SCIPgetValsLinear( 308 SCIP* scip, /**< SCIP data structure */ 309 SCIP_CONS* cons /**< constraint data */ 310 ); 311 312 /** gets the activity of the linear constraint in the given solution 313 * 314 * @note if the solution contains values at infinity, this method will return SCIP_INVALID in case the activity 315 * comprises positive and negative infinity contributions 316 */ 317 SCIP_EXPORT 318 SCIP_Real SCIPgetActivityLinear( 319 SCIP* scip, /**< SCIP data structure */ 320 SCIP_CONS* cons, /**< constraint data */ 321 SCIP_SOL* sol /**< solution, or NULL to use current node's solution */ 322 ); 323 324 /** gets the feasibility of the linear constraint in the given solution */ 325 SCIP_EXPORT 326 SCIP_Real SCIPgetFeasibilityLinear( 327 SCIP* scip, /**< SCIP data structure */ 328 SCIP_CONS* cons, /**< constraint data */ 329 SCIP_SOL* sol /**< solution, or NULL to use current node's solution */ 330 ); 331 332 /** gets the dual solution of the linear constraint in the current LP */ 333 SCIP_EXPORT 334 SCIP_Real SCIPgetDualsolLinear( 335 SCIP* scip, /**< SCIP data structure */ 336 SCIP_CONS* cons /**< constraint data */ 337 ); 338 339 /** gets the dual Farkas value of the linear constraint in the current infeasible LP */ 340 SCIP_EXPORT 341 SCIP_Real SCIPgetDualfarkasLinear( 342 SCIP* scip, /**< SCIP data structure */ 343 SCIP_CONS* cons /**< constraint data */ 344 ); 345 346 /** returns the linear relaxation of the given linear constraint; may return NULL if no LP row was yet created; 347 * the user must not modify the row! 348 */ 349 SCIP_EXPORT 350 SCIP_ROW* SCIPgetRowLinear( 351 SCIP* scip, /**< SCIP data structure */ 352 SCIP_CONS* cons /**< constraint data */ 353 ); 354 355 /** tries to automatically convert a linear constraint into a more specific and more specialized constraint */ 356 SCIP_EXPORT 357 SCIP_RETCODE SCIPupgradeConsLinear( 358 SCIP* scip, /**< SCIP data structure */ 359 SCIP_CONS* cons, /**< source constraint to try to convert */ 360 SCIP_CONS** upgdcons /**< pointer to store upgraded constraint, or NULL if not successful */ 361 ); 362 363 /** performs linear constraint type classification as used for MIPLIB 364 * 365 * iterates through all linear constraints and stores relevant statistics in the linear constraint statistics \p linconsstats. 366 * 367 * @note only constraints are iterated that belong to the linear constraint handler. If the problem has been presolved already, 368 * constraints that were upgraded to more special types such as, e.g., varbound constraints, will not be shown correctly anymore. 369 * Similarly, if specialized constraints were created through the API, these are currently not present. 370 */ 371 SCIP_EXPORT 372 SCIP_RETCODE SCIPclassifyConstraintTypesLinear( 373 SCIP* scip, /**< SCIP data structure */ 374 SCIP_LINCONSSTATS* linconsstats /**< linear constraint type classification */ 375 ); 376 377 378 /** cleans up (multi-)aggregations and fixings from linear constraints */ 379 SCIP_EXPORT 380 SCIP_RETCODE SCIPcleanupConssLinear( 381 SCIP* scip, /**< SCIP data structure */ 382 SCIP_Bool onlychecked, /**< should only checked constraints be cleaned up? */ 383 SCIP_Bool* infeasible /**< pointer to return whether the problem was detected to be infeasible */ 384 ); 385 386 /** @} */ 387 388 /** @} */ 389 390 #ifdef __cplusplus 391 } 392 #endif 393 394 #endif 395