ClingoBackend

Implements all basic clingo functionality for single-shot solving.

Examples

• sudoku_single_shot

class ClingoBackend(args)

The ClingoBackend contains the basic clingo functionality for a backend using clingo.

When started it sets up all the arguments provided via the command line, and creates a control object (domain-control) with the provided domain files. It grounds the program and creates an empty UI state.

add_atom(predicate)

Adds an assumption, restarts the control and grounds again

Parameters

predicate (str) – The clingo symbol to be added

clear_atoms()

Removes all atoms and resets the backend (i.e. it regrounds, etc.) and finally updates the model and returns the updated gui as a Json structure.

download(show_prg=None, file_name='clinguin_download.lp', domain_files=True)

Downloads the current state of the backend. All added atoms and assumptions are put together as a list of facts.

Parameters

• show_prg (_type_, optional) – Program to filter output using show statements. Defaults to None.

• file_name (str, optional) – The name of the file for the download. Defaults to “clinguin_download.lp”.

• domain_files (bool, optional) – If the domain files should be included. Defaults to True

next_solution(opt_mode='ignore')

Obtains the next solution. If a no browsing has been started yet, then it calls solve, otherwise it iterates the models in the last call.

Parameters

opt_mode – The clingo optimization mode, bu default is ‘ignore’, to browse only optimal models use ‘optN’

remove_atom(predicate)

Removes an assumption, restarts the control and grounds again

Parameters

predicate (str) – The clingo symbol to be added

restart()

Restarts the backend by initializing parameters, controls, ending the browsing grounding and updating the UI

select()

Select the current solution during browsing. All atoms in the solution are added as atoms in the backend.

update()

Updates the UI and transforms the output into a JSON.

Domain state constructors

The domain state also inclues domain constructors from the parent class.

ClingoBackend._ds_context()

Gets the context as facts _clinguin_context(KEY, VALUE)

ClingoBackend._ds_brave()

Computes brave consequences adds them as predicates _any/1.

It uses a cache that is erased after an operation makes changes in the control.

ClingoBackend._ds_cautious()

Computes cautious consequences adds them as predicates _all/1.

It uses a cache that is erased after an operation makes changes in the control.

ClingoBackend._ds_model()

Computes a model if one has not been set yet. When the model is being iterated by the user, the current model is returned. It uses a cache that is erased after an operation makes changes in the control.

ClingoBackend._ds_unsat()

Adds information about the statisfiablity of the domain control

Includes predicate _clinguin_unsat/0 if the domain control is unsat

ClingoBackend._ds_browsing()

Adds information about the browsing state

Includes predicate _clinguin_browsing/0 if the user is browsing solutions