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24   	
25   	/**@file   cons_linking.h
26   	 * @ingroup CONSHDLRS
27   	 * @brief  constraint handler for linking binary variables to a linking (continuous or integer) variable
28   	 * @author Stefan Heinz
29   	 * @author Jens Schulz
30   	 *
31   	 */
32   	
33   	/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
34   	
35   	#ifndef __SCIP_CONS_LINKING_H__
36   	#define __SCIP_CONS_LINKING_H__
37   	
38   	
39   	#include "scip/def.h"
40   	#include "scip/type_cons.h"
41   	#include "scip/type_retcode.h"
42   	#include "scip/type_scip.h"
43   	#include "scip/type_var.h"
44   	
45   	#ifdef __cplusplus
46   	extern "C" {
47   	#endif
48   	
49   	/** creates the handler for linking constraints and includes it in SCIP
50   	 *
51   	 * @ingroup ConshdlrIncludes
52   	 * */
53   	SCIP_EXPORT
54   	SCIP_RETCODE SCIPincludeConshdlrLinking(
55   	   SCIP*                 scip                /**< SCIP data structure */
56   	   );
57   	
58   	/**@addtogroup CONSHDLRS
59   	 *
60   	 * @{
61   	 *
62   	 * @name Linking Constraints
63   	 *
64   	 * @{
65   	 *
66   	 * The constraints handler stores linking constraints between a linking variable (continuous or integer) and an array of binary variables. Such
67   	 * a linking constraint has the form:
68   	 * \f[
69   	 * y = \sum_{i=1}^n {c_i * x_i}
70   	 * \f]
71   	 * with linking variable (continuous or integer) \f$ y \f$, binary variables \f$ x_1, \dots, x_n \f$ and offset \f$b \in Q\f$, and
72   	 * with the additional side condition that exactly one binary variable has to be one (set partitioning condition).
73   	 *
74   	 * This constraint can be created only with the linking variable, if it is an integer variable. In this case the binary variables are only created on
75   	 * demand. That is, whenever someone asks for the binary variables. Therefore, such constraints can be used to get a
76   	 * "binary representation" of the domain of the linking variable which will be dynamically created.
77   	 */
78   	
79   	/** creates and captures a linking constraint
80   	 *
81   	 *  @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
82   	 */
83   	SCIP_EXPORT
84   	SCIP_RETCODE SCIPcreateConsLinking(
85   	   SCIP*                 scip,               /**< SCIP data structure */
86   	   SCIP_CONS**           cons,               /**< pointer to hold the created constraint */
87   	   const char*           name,               /**< name of constraint */
88   	   SCIP_VAR*             linkvar,            /**< linking variable (continuous or integer) which should be linked */
89   	   SCIP_VAR**            binvars,            /**< binary variables */
90   	   SCIP_Real*            vals,               /**< coefficients of the binary variables */
91   	   int                   nbinvars,           /**< number of binary starting variables */
92   	   SCIP_Bool             initial,            /**< should the LP relaxation of constraint be in the initial LP?
93   	                                              *   Usually set to TRUE. Set to FALSE for 'lazy constraints'. */
94   	   SCIP_Bool             separate,           /**< should the constraint be separated during LP processing?
95   	                                              *   Usually set to TRUE. */
96   	   SCIP_Bool             enforce,            /**< should the constraint be enforced during node processing?
97   	                                              *   TRUE for model constraints, FALSE for additional, redundant constraints. */
98   	   SCIP_Bool             check,              /**< should the constraint be checked for feasibility?
99   	                                              *   TRUE for model constraints, FALSE for additional, redundant constraints. */
100  	   SCIP_Bool             propagate,          /**< should the constraint be propagated during node processing?
101  	                                              *   Usually set to TRUE. */
102  	   SCIP_Bool             local,              /**< is constraint only valid locally?
103  	                                              *   Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */
104  	   SCIP_Bool             modifiable,         /**< is constraint modifiable (subject to column generation)?
105  	                                              *   Usually set to FALSE. In column generation applications, set to TRUE if pricing
106  	                                              *   adds coefficients to this constraint. */
107  	   SCIP_Bool             dynamic,            /**< is constraint subject to aging?
108  	                                              *   Usually set to FALSE. Set to TRUE for own cuts which
109  	                                              *   are separated as constraints. */
110  	   SCIP_Bool             removable,          /**< should the relaxation be removed from the LP due to aging or cleanup?
111  	                                              *   Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */
112  	   SCIP_Bool             stickingatnode      /**< should the constraint always be kept at the node where it was added, even
113  	                                              *   if it may be moved to a more global node?
114  	                                              *   Usually set to FALSE. Set to TRUE to for constraints that represent node data. */
115  	   );
116  	
117  	/** creates and captures a linking constraint
118  	 *  in its most basic version, i. e., all constraint flags are set to their basic value as explained for the
119  	 *  method SCIPcreateConsLinking(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h
120  	 *
121  	 *  @see SCIPcreateConsLinking() for information about the basic constraint flag configuration
122  	 *
123  	 *  @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()
124  	 */
125  	SCIP_EXPORT
126  	SCIP_RETCODE SCIPcreateConsBasicLinking(
127  	   SCIP*                 scip,               /**< SCIP data structure */
128  	   SCIP_CONS**           cons,               /**< pointer to hold the created constraint */
129  	   const char*           name,               /**< name of constraint */
130  	   SCIP_VAR*             linkvar,            /**< linking variable (continuous or integer) which should be linked */
131  	   SCIP_VAR**            binvars,            /**< binary variables, or NULL */
132  	   SCIP_Real*            vals,               /**< coefficients of the binary variables */
133  	   int                   nbinvars            /**< number of binary variables */
134  	   );
135  	
136  	
137  	/** checks if for the given linking variable (continuous or integer) a linking constraint exists */
138  	SCIP_EXPORT
139  	SCIP_Bool SCIPexistsConsLinking(
140  	   SCIP*                 scip,               /**< SCIP data structure */
141  	   SCIP_VAR*             linkvar             /**< linking variable (continuous or integer) which should be linked */
142  	   );
143  	
144  	/** returns the linking constraint belonging the given linking variable (continuous or integer) or NULL if it does not exist yet */
145  	SCIP_EXPORT
146  	SCIP_CONS* SCIPgetConsLinking(
147  	   SCIP*                 scip,               /**< SCIP data structure */
148  	   SCIP_VAR*             linkvar             /**< linking variable (continuous or integer) which should be linked */
149  	   );
150  	
151  	/** returns the linking variable (continuous or integer) of the linking constraint */
152  	SCIP_EXPORT
153  	SCIP_VAR* SCIPgetLinkvarLinking(
154  	   SCIP*                 scip,               /**< SCIP data structure */
155  	   SCIP_CONS*            cons                /**< linking constraint */
156  	   );
157  	
158  	/** returns the binary variables of the linking constraint */
159  	SCIP_EXPORT
160  	SCIP_RETCODE SCIPgetBinvarsLinking(
161  	   SCIP*                 scip,               /**< SCIP data structure */
162  	   SCIP_CONS*            cons,               /**< linking constraint */
163  	   SCIP_VAR***           binvars,            /**< pointer to store the binary variables array pointer */
164  	   int*                  nbinvars            /**< pointer to store the number of returned binary variables */
165  	   );
166  	
167  	/** returns the number of binary variables of the linking constraint */
168  	SCIP_EXPORT
169  	int SCIPgetNBinvarsLinking(
170  	   SCIP*                 scip,               /**< SCIP data structure */
171  	   SCIP_CONS*            cons                /**< linking constraint */
172  	   );
173  	
174  	/** returns the coefficients of the binary variables */
175  	SCIP_EXPORT
176  	SCIP_Real* SCIPgetValsLinking(
177  	   SCIP*                 scip,               /**< SCIP data structure */
178  	   SCIP_CONS*            cons                /**< linking constraint */
179  	   );
180  	
181  	/** return all binary variable information of the linking constraint */
182  	SCIP_EXPORT
183  	SCIP_RETCODE SCIPgetBinvarsDataLinking(
184  	   SCIP_CONS*            cons,               /**< linking constraint */
185  	   SCIP_VAR***           binvars,            /**< pointer to store binary variables, or NULL */
186  	   SCIP_Real**           vals,               /**< pointer to store the binary coefficients, or NULL */
187  	   int*                  nbinvars            /**< pointer to store the number of binary variables, or NULL */
188  	   );
189  	
190  	/** @} */
191  	
192  	/** @} */
193  	
194  	#ifdef __cplusplus
195  	}
196  	#endif
197  	
198  	#endif
199