#34 Infinite loop in local stratification algorithm

[baz bishop]

The following rule set causes the LocalStratifier to enter an infinite loop.

e1(?v6) :- e3(0, ?v7, 3), !e5(?v0, ?v6, 0, 1, ?v3), !EQUAL(4, ?v7), !e2(?v6, ?v3), !e3(2, ?v0, 0), i1(?v6).

e5(?v2, ?v6, ?v0, ?v0, ?v2) :- e2(?v0, ?v4), EQUAL(?v0, ?v6), e2(?v2, ?v0), e4(?v5, ?v6, ?v1, ?v6), i4(?v6, 2, 2, ?v2).

e3(?v1, 4, ?v6) :- e4(0, ?v7, 4, ?v4), !e1(5), i2(?v1, ?v1), e5(?v2, ?v1, ?v4, ?v4, 4), i1(?v6).

[baz bishop]

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The rule set can be reduced to this:

e1(?v6) :- e3(0, 3), !e5(0, 1), i1(?v6).
e5(?v0, ?v0) :- EQUAL(?v0, ?v6), i2(?v0,?v6).
e3(?v1, ?v6) :- !e1(5), i2(?v6, ?v1).

to generate the same problem.

[baz bishop]

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**When this bug is fixed, remove the lines from the EvaluationComparisonStressTest class that disable the local stratifier.**