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 expr_pow.h 26 * @ingroup EXPRHDLRS 27 * @brief power and signed power expression handlers 28 * @author Benjamin Mueller 29 */ 30 31 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 32 33 #ifndef __SCIP_EXPR_POW_H__ 34 #define __SCIP_EXPR_POW_H__ 35 36 #include "scip/scip.h" 37 #include "scip/type_expr.h" 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif 42 43 /**@addtogroup EXPRHDLRS 44 * 45 * @{ 46 * 47 * @name Power and signed power expression 48 * 49 * These expression handlers provide the power function, that is, 50 * \f[ 51 * x \mapsto \begin{cases} 52 * x^e & \textrm{if}\; x \geq 0\; \textrm{or}\; e\in\mathbb{Z}, \\ 53 * \textrm{undefined}, & \textrm{otherwise}. 54 * \end{cases} 55 * \f] 56 * and the signed power function, that is, 57 * \f[ 58 * x \mapsto \textrm{sign}(x) |x|^e 59 * \f] 60 * for some exponent \f$e\f$. 61 * 62 * @{ 63 */ 64 65 /** creates a power expression */ 66 SCIP_EXPORT 67 SCIP_RETCODE SCIPcreateExprPow( 68 SCIP* scip, /**< SCIP data structure */ 69 SCIP_EXPR** expr, /**< pointer where to store expression */ 70 SCIP_EXPR* child, /**< single child */ 71 SCIP_Real exponent, /**< exponent of the power expression */ 72 SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), /**< function to call to create ownerdata */ 73 void* ownercreatedata /**< data to pass to ownercreate */ 74 ); 75 76 /** creates a signpower expression */ 77 SCIP_EXPORT 78 SCIP_RETCODE SCIPcreateExprSignpower( 79 SCIP* scip, /**< SCIP data structure */ 80 SCIP_EXPR** expr, /**< pointer where to store expression */ 81 SCIP_EXPR* child, /**< single child */ 82 SCIP_Real exponent, /**< exponent of the power expression */ 83 SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), /**< function to call to create ownerdata */ 84 void* ownercreatedata /**< data to pass to ownercreate */ 85 ); 86 87 /** indicates whether expression is of signpower-type */ 88 SCIP_EXPORT 89 SCIP_Bool SCIPisExprSignpower( 90 SCIP* scip, /**< SCIP data structure */ 91 SCIP_EXPR* expr /**< expression */ 92 ); 93 94 /** @} 95 * @} 96 */ 97 98 /** creates the handler for power expression and includes it into SCIP 99 * 100 * @ingroup ExprhdlrIncludes 101 */ 102 SCIP_EXPORT 103 SCIP_RETCODE SCIPincludeExprhdlrPow( 104 SCIP* scip /**< SCIP data structure */ 105 ); 106 107 /** creates the handler for signed power expression and includes it into SCIP 108 * 109 * @ingroup ExprhdlrIncludes 110 */ 111 SCIP_EXPORT 112 SCIP_RETCODE SCIPincludeExprhdlrSignpower( 113 SCIP* scip /**< SCIP data structure */ 114 ); 115 116 /** computes coefficients of linearization of a square term in a reference point */ 117 SCIP_EXPORT 118 void SCIPaddSquareLinearization( 119 SCIP* scip, /**< SCIP data structure */ 120 SCIP_Real sqrcoef, /**< coefficient of square term */ 121 SCIP_Real refpoint, /**< point where to linearize */ 122 SCIP_Bool isint, /**< whether corresponding variable is a discrete variable, and thus linearization could be moved */ 123 SCIP_Real* lincoef, /**< buffer to add coefficient of linearization */ 124 SCIP_Real* linconstant, /**< buffer to add constant of linearization */ 125 SCIP_Bool* success /**< buffer to set to FALSE if linearization has failed due to large numbers */ 126 ); 127 128 /** computes coefficients of secant of a square term */ 129 SCIP_EXPORT 130 void SCIPaddSquareSecant( 131 SCIP* scip, /**< SCIP data structure */ 132 SCIP_Real sqrcoef, /**< coefficient of square term */ 133 SCIP_Real lb, /**< lower bound on variable */ 134 SCIP_Real ub, /**< upper bound on variable */ 135 SCIP_Real* lincoef, /**< buffer to add coefficient of secant */ 136 SCIP_Real* linconstant, /**< buffer to add constant of secant */ 137 SCIP_Bool* success /**< buffer to set to FALSE if secant has failed due to large numbers or unboundedness */ 138 ); 139 140 /** Separation for roots with exponent in [0,1] */ 141 SCIP_EXPORT 142 void SCIPestimateRoot( 143 SCIP* scip, /**< SCIP data structure */ 144 SCIP_Real exponent, /**< exponent */ 145 SCIP_Bool overestimate, /**< should the power be overestimated? */ 146 SCIP_Real xlb, /**< lower bound on x */ 147 SCIP_Real xub, /**< upper bound on x */ 148 SCIP_Real xref, /**< reference point (where to linearize) */ 149 SCIP_Real* constant, /**< buffer to store constant term of estimator */ 150 SCIP_Real* slope, /**< buffer to store slope of estimator */ 151 SCIP_Bool* islocal, /**< buffer to store whether estimator only locally valid, that is, 152 it depends on given bounds */ 153 SCIP_Bool* success /**< buffer to store whether estimator could be computed */ 154 ); 155 156 #ifdef __cplusplus 157 } 158 #endif 159 160 #endif /* __SCIP_EXPR_POW_H__ */ 161