GraphBacktracking reports diagnostic information through the info class InfoGB, which is set equal to the BacktrackKit info class InfoBTKit (BacktrackKit: InfoBTKit); raising the level of either (with SetInfoLevel) therefore raises both. Higher levels print progressively more detail about the progress of the search.
These three functions are the graph backtracking analogues of the BacktrackKit search functions BTKit_SimpleSearch (BacktrackKit: BTKit_SimpleSearch), BTKit_SimpleSinglePermSearch (BacktrackKit: BTKit_SimpleSinglePermSearch) and BTKit_SimpleAllPermSearch (BacktrackKit: BTKit_SimpleAllPermSearch), and take the same arguments. Each begins from the ordered partition stack ps (see PartitionStack (BacktrackKit: PartitionStack)) and searches for the permutations that satisfy every refiner in the list conlist. Refiners may be built with the constructors in the GB_Con record (see 3) or with any BacktrackKit refiner. The optional final argument conf is a configuration record; the recognised fields are cellSelector (the branch-cell selector) and consolidator (the function used to make the graph stack equitable, see 4).
‣ GB_SimpleSearch( ps, conlist[, conf] ) | ( function ) |
Returns: a permutation group
Returns the group of all permutations that satisfy every refiner in conlist. This is correct only when that set of permutations is in fact a group (for example, an intersection of groups, a stabiliser, or a normaliser); use GB_SimpleSinglePermSearch (2.2-2) when the solution set is a coset.
‣ GB_SimpleSinglePermSearch( ps, conlist[, conf] ) | ( function ) |
Returns: a permutation, or fail
Returns a single permutation satisfying every refiner in conlist, or fail if no such permutation exists. This is the function to use for coset and transporter problems (group or coset intersection, conjugacy, and so on).
‣ GB_SimpleAllPermSearch( ps, conlist[, conf] ) | ( function ) |
Returns: a list of permutations
Returns the complete list of permutations satisfying every refiner in conlist. This enumerates the whole solution set and is therefore very slow; it is intended for testing and exploration on small examples.
These functions expose the graph stack that is built before any branching takes place. They are used mainly for testing and for understanding how much a set of refiners deduces for free
, and are unlikely to be needed in ordinary use.
‣ GB_CheckInitialGroup( ps, conlist ) | ( function ) |
Returns: a record
Builds the initial graph stack for conlist and returns a record with components gens (generators of the automorphism group of the initial stack, as permutations) and answer (true if every one of those generators already satisfies conlist, so that no search is required; false otherwise, in which case the group is a supergroup of the solutions).
‣ GB_CheckInitialCoset( ps, conlist ) | ( function ) |
Returns: a record
The coset analogue of GB_CheckInitialGroup (2.3-1). Builds the initial graph stack down both the left and the right branch and returns a record with components graph1, graph2 (the two canonically-labelled graph stacks) and equal (whether they coincide).
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