potassco / potassco/constraint-handler

Passing the output of a propagator `execution_declare/5` constraint to a non-propagator constraint

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Python
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Description

Say I have an execution_declare/5 constraint that assigns a value to some output and then I have an ensure/2 constraint that enforces some requirement. For example,

execution_declare(c1,c1,assign(a,val(int,1),(),(a,())
ensure(c2,operation(gt, (variable(execution_output(c1,a)), (val(int,0),())))).

In general I understand that if c1 is handled by the propagator engine then c2 must also be handled by the propagator engine. So currently the following won't work:

requestEngine(c1, propagator).
requestEngine(c2, compile).

However, it should be possible to provide extra information that fully specifies the domain for execution_output(c1,a) in which case all possible output values can be grounded in ASP and then passed to c2.

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Research direction

Start with the execution_declare/5 and ensure/2 constraint paths, then trace how requestEngine selects the propagator or compile engine. Determine how fully specified execution_output values could be grounded and handed to a non-propagator constraint; done means the c1/c2 scenario works with c1 using propagator and c2 using compile.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
35/100

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