Scippy

    SCIP

    Solving Constraint Integer Programs

    Macros | Typedefs | Enumerations
    type_heur.h File Reference
    Public API of SCIP » Core API » Type Definitions

    Detailed Description

    type definitions for primal heuristics

    Author
    Tobias Achterberg
    Timo Berthold

    This file defines the interface for primal heuristics implemented in C.

    Definition in file type_heur.h.

    #include "scip/def.h"
    #include "scip/type_scip.h"
    #include "scip/type_result.h"
    #include "scip/type_timing.h"
    #include "scip/type_var.h"

    Go to the source code of this file.

    Macros

    #define SCIP_DIVETYPE_NONE   0x000u
     
    #define SCIP_DIVETYPE_INTEGRALITY   0x001u
     
    #define SCIP_DIVETYPE_SOS1VARIABLE   0x002u
     
    #define SCIP_HEURDISPCHAR_LNS   'L'
     
    #define SCIP_HEURDISPCHAR_DIVING   'd'
     
    #define SCIP_HEURDISPCHAR_ITERATIVE   'i'
     
    #define SCIP_HEURDISPCHAR_OBJDIVING   'o'
     
    #define SCIP_HEURDISPCHAR_PROP   'p'
     
    #define SCIP_HEURDISPCHAR_ROUNDING   'r'
     
    #define SCIP_HEURDISPCHAR_TRIVIAL   't'
     
    #define SCIP_DECL_HEURCOPY(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEURFREE(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEURINIT(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEUREXIT(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEURINITSOL(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEUREXITSOL(x)   SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)
     
    #define SCIP_DECL_HEUREXEC(x)
     
    #define SCIP_DECL_DIVESETGETSCORE(x)
     
    #define SCIP_DECL_DIVESETAVAILABLE(x)   SCIP_RETCODE x (SCIP* scip, SCIP_DIVESET* diveset, SCIP_Bool* available)
     

    Typedefs

    typedef unsigned int SCIP_DIVETYPE
     
    typedef enum SCIP_DiveContext SCIP_DIVECONTEXT
     
    typedef struct SCIP_Heur SCIP_HEUR
     
    typedef struct SCIP_HeurData SCIP_HEURDATA
     
    typedef struct SCIP_Diveset SCIP_DIVESET
     
    typedef struct SCIP_VGraph SCIP_VGRAPH
     

    Enumerations

    enum  SCIP_DiveContext {
      SCIP_DIVECONTEXT_TOTAL = 0 ,
      SCIP_DIVECONTEXT_SINGLE = 1 ,
      SCIP_DIVECONTEXT_ADAPTIVE = 2 ,
      SCIP_DIVECONTEXT_SCHEDULER = 3
    }
     

    Macro Definition Documentation

    ◆ SCIP_DIVETYPE_NONE

    #define SCIP_DIVETYPE_NONE   0x000u

    represents different methods for a dive set to explore the next children no method specified

    Definition at line 59 of file type_heur.h.

    ◆ SCIP_DIVETYPE_INTEGRALITY

    #define SCIP_DIVETYPE_INTEGRALITY   0x001u

    use branching on a variable by shrinking the domain in the child nodes

    Definition at line 60 of file type_heur.h.

    ◆ SCIP_DIVETYPE_SOS1VARIABLE

    #define SCIP_DIVETYPE_SOS1VARIABLE   0x002u

    branch on a variable solution value by exploiting special-ordered set conflict structure

    Definition at line 61 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_LNS

    #define SCIP_HEURDISPCHAR_LNS   'L'

    commonly used display characters indicating special classes of primal heuristics a 'L'arge Neighborhood or other local search heuristic

    Definition at line 83 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_DIVING

    #define SCIP_HEURDISPCHAR_DIVING   'd'

    a 'd'iving heuristic that dives down an auxiliary branch-and-bound path

    Definition at line 84 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_ITERATIVE

    #define SCIP_HEURDISPCHAR_ITERATIVE   'i'

    an iterative improvement heuristic such as 1-opt or 2-opt

    Definition at line 85 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_OBJDIVING

    #define SCIP_HEURDISPCHAR_OBJDIVING   'o'

    an 'o'bjective diving or feasibility pump heuristic

    Definition at line 86 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_PROP

    #define SCIP_HEURDISPCHAR_PROP   'p'

    a 'p'ropagation heuristic, often applied before branch-and-bound starts

    Definition at line 87 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_ROUNDING

    #define SCIP_HEURDISPCHAR_ROUNDING   'r'

    a 'r'ounding heuristic that iteratively tries to round an LP or relaxation solution

    Definition at line 88 of file type_heur.h.

    ◆ SCIP_HEURDISPCHAR_TRIVIAL

    #define SCIP_HEURDISPCHAR_TRIVIAL   't'

    a 't'rivial or helper heuristic, usually applied before branch-and-bound starts

    Definition at line 89 of file type_heur.h.

    ◆ SCIP_DECL_HEURCOPY

    #define SCIP_DECL_HEURCOPY (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    copy method for heuristic plugins (called when SCIP copies plugins)

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 97 of file type_heur.h.

    ◆ SCIP_DECL_HEURFREE

    #define SCIP_DECL_HEURFREE (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    destructor of primal heuristic to free user data (called when SCIP is exiting)

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 105 of file type_heur.h.

    ◆ SCIP_DECL_HEURINIT

    #define SCIP_DECL_HEURINIT (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    initialization method of primal heuristic (called after problem was transformed)

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 113 of file type_heur.h.

    ◆ SCIP_DECL_HEUREXIT

    #define SCIP_DECL_HEUREXIT (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    deinitialization method of primal heuristic (called before transformed problem is freed)

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 121 of file type_heur.h.

    ◆ SCIP_DECL_HEURINITSOL

    #define SCIP_DECL_HEURINITSOL (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    solving process initialization method of primal heuristic (called when branch and bound process is about to begin)

    This method is called when the presolving was finished and the branch and bound process is about to begin. The primal heuristic may use this call to initialize its branch and bound specific data.

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 132 of file type_heur.h.

    ◆ SCIP_DECL_HEUREXITSOL

    #define SCIP_DECL_HEUREXITSOL (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur)

    solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)

    This method is called before the branch and bound process is freed. The primal heuristic should use this call to clean up its branch and bound data.

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself

    Definition at line 143 of file type_heur.h.

    ◆ SCIP_DECL_HEUREXEC

    #define SCIP_DECL_HEUREXEC (   x)
    Value:
    SCIP_RETCODE x (SCIP* scip, SCIP_HEUR* heur, SCIP_HEURTIMING heurtiming, \
    SCIP_Bool nodeinfeasible, SCIP_RESULT* result)
    x
    SCIP_VAR ** x
    Definition: circlepacking.c:63
    SCIP_Bool
    #define SCIP_Bool
    Definition: def.h:91
    SCIP_Heur
    Definition: struct_heur.h:98
    SCIP_RESULT
    enum SCIP_Result SCIP_RESULT
    Definition: type_result.h:61
    SCIP_RETCODE
    enum SCIP_Retcode SCIP_RETCODE
    Definition: type_retcode.h:63
    SCIP_HEURTIMING
    unsigned int SCIP_HEURTIMING
    Definition: type_timing.h:103

    execution method of primal heuristic

    Searches for feasible primal solutions. The method is called in the node processing loop.

    input:

    • scip : SCIP main data structure
    • heur : the primal heuristic itself
    • heurtiming : current point in the node solving loop
    • nodeinfeasible : was the current node already detected to be infeasible?
    • result : pointer to store the result of the heuristic call

    possible return values for *result:

    • SCIP_FOUNDSOL : at least one feasible primal solution was found
    • SCIP_DIDNOTFIND : the heuristic searched, but did not find a feasible solution
    • SCIP_DIDNOTRUN : the heuristic was skipped
    • SCIP_DELAYED : the heuristic was skipped, but should be called again as soon as possible, disregarding its frequency

    Definition at line 163 of file type_heur.h.

    ◆ SCIP_DECL_DIVESETGETSCORE

    #define SCIP_DECL_DIVESETGETSCORE (   x)
    Value:
    SCIP_RETCODE x (SCIP* scip, SCIP_DIVESET* diveset, \
    SCIP_DIVETYPE divetype, SCIP_VAR* cand, SCIP_Real candsol, SCIP_Real candsfrac, SCIP_Real* score, SCIP_Bool* roundup)
    SCIP_Real
    #define SCIP_Real
    Definition: def.h:156
    SCIP_Diveset
    Definition: struct_heur.h:68
    SCIP_Var
    Definition: struct_var.h:262
    SCIP_DIVETYPE
    unsigned int SCIP_DIVETYPE
    Definition: type_heur.h:63

    calculate score and preferred rounding direction for the candidate variable; the best candidate maximizes the score

    input:

    • scip : SCIP main data structure
    • diveset : diving settings for scoring
    • divetype : represents different methods for a dive set to explore the next children
    • cand : candidate variable for which the score should be determined
    • candsol : solution value of variable in LP relaxation solution
    • candsfrac : fractional part of solution value of variable
    • score : pointer for diving score value - the best candidate maximizes this score
    • roundup : pointer to store whether the preferred rounding direction is upwards

    returns SCIP_OKAY if everything worked, otherwise, a suitable error code

    Definition at line 184 of file type_heur.h.

    ◆ SCIP_DECL_DIVESETAVAILABLE

    #define SCIP_DECL_DIVESETAVAILABLE (   x)    SCIP_RETCODE x (SCIP* scip, SCIP_DIVESET* diveset, SCIP_Bool* available)

    optional callback to check preconditions for diving, e.g., if an incumbent solution is available

    input:

    • scip : SCIP main data structure
    • diveset : diving settings for scoring

    output:

    • available : TRUE if diveset can run, otherwise FALSE

    returns SCIP_OKAY if everything worked, otherwise, a suitable error code

    Definition at line 199 of file type_heur.h.

    Typedef Documentation

    ◆ SCIP_DIVETYPE

    typedef unsigned int SCIP_DIVETYPE

    Definition at line 63 of file type_heur.h.

    ◆ SCIP_DIVECONTEXT

    typedef enum SCIP_DiveContext SCIP_DIVECONTEXT

    Definition at line 73 of file type_heur.h.

    ◆ SCIP_HEUR

    typedef struct SCIP_Heur SCIP_HEUR

    primal heuristic

    Definition at line 76 of file type_heur.h.

    ◆ SCIP_HEURDATA

    typedef struct SCIP_HeurData SCIP_HEURDATA

    locally defined primal heuristic data

    Definition at line 77 of file type_heur.h.

    ◆ SCIP_DIVESET

    typedef struct SCIP_Diveset SCIP_DIVESET

    common parameters for all diving heuristics

    Definition at line 78 of file type_heur.h.

    ◆ SCIP_VGRAPH

    typedef struct SCIP_VGraph SCIP_VGRAPH

    variable graph data structure to determine breadth-first distances between variables

    Definition at line 79 of file type_heur.h.

    Enumeration Type Documentation

    ◆ SCIP_DiveContext

    enum SCIP_DiveContext

    context for diving statistics

    Enumerator
    SCIP_DIVECONTEXT_TOTAL 

    all contexts combined

    SCIP_DIVECONTEXT_SINGLE 

    single heuristic context

    SCIP_DIVECONTEXT_ADAPTIVE 

    within adaptive diving

    SCIP_DIVECONTEXT_SCHEDULER 

    within the scheduler heuristic

    Definition at line 66 of file type_heur.h.