How to add decomposition scores

GCG uses scores to rate decompositions that are found by the detection. To continuously prefer different decompositions than GCG does by default with its set partitioning foreseeing max white score, you can program your own score.
A complete list of all scores contained in this release can be found here.

Adding your own Decomposition Score

With the following steps, we explain how you can add your own score to rate decompositions:

1. Preparations
   
   1. Choose a name myscore for your decomposition score.
   2. In the file class_partialdecomp.h, initialize your score:
      • In the class PARTIALDECOMP::PARTIALDECOMP(SCIP* _scip, ...), initialize it below the line bool originalProblem by adding myscore( -1. ),.
      • In the class PARTIALDECOMP::PARTIALDECOMP(const PARTIALDECOMP *partialdectocopy), add it to the partial decomposition to copy by adding myscore = partialdectocopy->myscore;
   3. [optional] In the function void PARTIALDECOMP::displayInfo(int detailLevel), add an output for the statistics for your score.
   4. Add a real variable myscore for your score to the class PARTIALDECOMP (below the section /* score values */).
2. Creating your Score
   In the file cons_decomp.cpp:
   1. Write your score calculation function with the following signature (as an example, you can have a look at the GCGconshdlrDecompCalcMaxWhiteScore() function):

      SCIP_RETCODE GCGconshdlrDecompCalcMyScore(
       SCIP* scip,
       int partialdecid,
       SCIP_Real* score
       )

   2. In the case switch in the function PARTIALDECOMP::getScore(type) in the file class_partialdecomp.h, add your calculation function.
   3. Add a getter and a setter function getMyScore() and setMyScore() (as an example, take the function getMaxWhiteScore()) in the file class_partialdecomp.h.
3. Make GCG use it
   Add your score to
   1. the arrays scoretype_shortnames and scoretype_descriptions in the file scoretype.c.
   2. the enum scoretype in the file type_scoretype.h.
   3. the struct Dec_Scores in the file pub_decomp.h.