The Explore Menu

The explore menu is a submenu in the interactive console. You can leave submenus (e.g. <explore> or <master>) with quit.

Using the explore menu

Enter the explore menu

First, you have to read and optimize, or at least detect your problem. Then, like with all commands, just type explore in the interactive shell. GCG will show an overview of all found decompositions:

GCG> explore
 
==================================================================================
Summary              presolved       original
                     ---------       --------
detected                     6              0
==================================================================================
   nr   id nbloc nmacon nlivar nmavar nstlva spfwh history  pre nopcon nopvar  sel
 ---- ---- ----- ------ ------ ------ ------ ----- ------- ---- ------ ------ ----
    0   13    50     50      0      0      0 0.745      cC  yes      0      0   no
    1   12    50     50      0     50      0 0.245      cC  yes      0      0   no
    2   15   100      0   2500      0      0 0.009      vC  yes      0      0   no
    3   16     1      0     50      0      0 0.006      vC  yes      0      0   no
    4   11     1      0      0      0      0 0.000       C  yes      0      0   no
    5   14     1      1      0      0      0 0.000      nC  yes      0      0   no
Please enter command or decomposition id to select (or "h" for help) :

In this table you can find very useful information about the decomposition GCG found for your problem. For example, the column history contains the sequence of detectors in the order that they worked on your problem. What exactly the letters mean can be found here. When typing h, you will get a list of possible commands:

GCG/explore> help
==================================================================================
 
List of selection commands
 
                       command     description
                       -------     -----------
                          help     displays this help
                        legend     displays the legend for table header and history abbreviations
                        select     selects/unselects decomposition with given nr
                      previous     displays the preceding decompositions (if there are any)
                          next     displays the subsequent decompositions (if there are any)
                           top     displays the first decompositions
                           end     displays the last decompositions
                       entries     modifies the number of decompositions to display per page
                     visualize     visualizes the specified decomposition (requires gnuplot)
                       inspect     displays detailed information for the specified decomposition
                         score     sets the score by which the quality of decompositions is evaluated
                          sort     sets the column by which the decompositions are sorted (default: by score)
                     ascending     sort decompositions in ascending (true) or descending (false) order
                          list     specify whether all decompositions should be listed
                          quit     return to main menu
 
 
==================================================================================

Select structures for solving with select

You can choose one of the decompositions to be used for solving with the select <id> command.

GCG/explore> select 2
==================================================================================
Please specify the nr of the decomposition to be selected:
 
==================================================================================
Summary              presolved       original
                     ---------       --------
detected                     6              0
==================================================================================
   nr   id nbloc nmacon nlivar nmavar nstlva spfwh history  pre nopcon nopvar  sel
 ---- ---- ----- ------ ------ ------ ------ ----- ------- ---- ------ ------ ----
    0   13    50     50      0      0      0 0.745      cC  yes      0      0   no
    1   12    50     50      0     50      0 0.245      cC  yes      0      0   no
    2   15   100      0   2500      0      0 0.009      vC  yes      0      0  yes
    3   16     1      0     50      0      0 0.006      vC  yes      0      0   no
    4   11     1      0      0      0      0 0.000       C  yes      0      0   no
    5   14     1      1      0      0      0 0.000      nC  yes      0      0   no
Please enter command or decomposition id to select (or "h" for help) :

After that, you can visualize (see below) the decomposition or also leave the explore menu (..) and optimize the problem. If you don't select a decomposition, GCG will always use the 'best' one, i.e. nr. 0 in the example above.

Visualize your decomposition with visualize

With the visualize command, you can export a visualization of the selected decomposition. Prior to that, you will have to install "gnuplot" by typing sudo apt-get install gnuplot into your console.

Use a different score with <tt>score</tt>

By default, GCG uses the so-called max white score. This means that the decomposition with the most zero entries is used. Since this might not always be the best measure, it is possible to choose a different score:

GCG/explore> score
==================================================================================
Please specify the new score:
0: max white,
1: border area,
2: classic,
3: max foreseeing white,
4: ppc-max-white,
5: max foreseeing white with aggregation info,
6: ppc-max-white with aggregation info,
7: experimental benders score
8: strong decomposition score
Note: Sets the detection/scoretype parameter to the given score.

Solve again with a different decomposition with free

If you now want to solve your problem with a different decomposition, you first have to clear the problem from GCG's memory with free. Then, read it in again and you are ready to select a different decomposition.