GenerateMultihistory

[maxitg]

Changes

• Implements GenerateMultihistory function.
• Also implements related introspection functions, i.e., $SetReplaceSystems, EventSelectionParameters, EventOrderingFunctions and StoppingConditionParameters.
• Also implements package-scope declareMultihistoryGenerator used to specify the kinds of event selections, orderings, and stopping conditions a system supports. GenerateMultihistory then does most of the arguments checking itself (although it is possible to throw and generate messages from the specific implementations).

Comments

• I did not write documentation yet, because it seems silly to write descriptions of things like event selection and token deduplication without having any examples to show. I will write documentation for both generators and MultisetSubstitutionSystem once both are merged.

Examples

• Declare a generator. Here, Infinity and 0 are the defaults, and "NonNegativeIntegerOrInfinity" enables automatic checking and is, in addition to None, is the only one supported at the moment (it is, by far, the most common).

SetReplace`PackageScope`declareMultihistoryGenerator[
  generateMultisetMultihistory,
  MultisetSubstitutionSystem,
  <|"MaxGeneration" -> {Infinity, "NonNegativeIntegerOrInfinity"},
    "MinEventInputs" -> {0, "NonNegativeIntegerOrInfinity"}|>,
  {"InputCount", "RuleOrdering"},
  <|"MaxEvents" -> {Infinity, "NonNegativeIntegerOrInfinity"}|>];
Unprotect[$SetReplaceSystems];
SetReplace`PackageScope`initializeGenerators[];

• Now, try to use the generator. Note that GenerateMultihistory automatically inserted the missing parameters. The first argument is passed unchanged:

In[] := GenerateMultihistory[
  MultisetSubstitutionSystem[1, 2], <|"MaxGeneration" -> 3|>, All, {"InputCount"}, {}][0]
Out[] = generateMultisetMultihistory[MultisetSubstitutionSystem[1, 2],
                                     <|"MaxGeneration" -> 3, "MinEventInputs" -> 0|>,
                                     All,
                                     {"InputCount"},
                                     <|"MaxEvents" -> \[Infinity]|>,
                                     0]

• Try to pass invalid or non-existing parameters will throw an error before ever reaching generateMultisetMultihistory:

In[] := GenerateMultihistory[
  MultisetSubstitutionSystem[1, 2], <|"MaxGeneration" -> -1|>, All, {"InputCount"}, {}][0]

Out[] = GenerateMultihistory[
  MultisetSubstitutionSystem[1, 2], <|"MaxGeneration" -> -1|>, All, {"InputCount"}, {}][0]

• Query the list of all systems available:

In[] := $SetReplaceSystems
Out[] = {MultisetSubstitutionSystem}

• Query the available parameters for a particular system:

In[] := Through[
  {EventSelectionParameters, EventOrderingFunctions, StoppingConditionParameters} @
    MultisetSubstitutionSystem]
Out[] = {{"MaxGeneration", "MinEventInputs"}, {"InputCount", "RuleOrdering"}, {"MaxEvents"}}

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This change is 

[maxitg]

@daneelsan, @taliesinb?