Discarding Order-Dependent Subalgebras (#14)

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Brandon Rozek 2025-02-09 11:29:57 -05:00 committed by GitHub
commit 2d8540f5c2
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4 changed files with 55 additions and 12 deletions

25
vsp.py
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@ -6,7 +6,7 @@ from itertools import chain, combinations, product
from typing import List, Optional, Set, Tuple
from common import set_to_str
from model import (
Model, model_closure, ModelFunction, ModelValue
Model, model_closure, ModelFunction, ModelValue, OrderTable
)
def preseed(
@ -78,6 +78,15 @@ def find_bottom(algebra: Set[ModelValue], mconjunction: Optional[ModelFunction],
print("[Warning] Failed to find the bottom of the lattice")
return None
def order_dependent(subalgebra1: Set[ModelValue], subalegbra2: Set[ModelValue], ordering: OrderTable):
"""
Returns true if there exists a value in subalgebra1 that's less than a value in subalgebra2
"""
for x in subalgebra1:
for y in subalegbra2:
if ordering.is_lt(x, y):
return True
return False
class VSP_Result:
def __init__(
@ -97,7 +106,10 @@ Subalgebra 1: {set_to_str(self.subalgebra1)}
Subalgebra 2: {set_to_str(self.subalgebra2)}
"""
def has_vsp(model: Model, impfunction: ModelFunction, mconjunction: Optional[ModelFunction] = None, mdisjunction: Optional[ModelFunction] = None) -> VSP_Result:
def has_vsp(model: Model, impfunction: ModelFunction,
mconjunction: Optional[ModelFunction] = None,
mdisjunction: Optional[ModelFunction] = None,
mnegation: Optional[ModelFunction] = None) -> VSP_Result:
"""
Checks whether a model has the variable
sharing property.
@ -110,6 +122,8 @@ def has_vsp(model: Model, impfunction: ModelFunction, mconjunction: Optional[Mod
if len(model.designated_values) == 1:
return VSP_Result(False, model.name)
assert model.ordering is not None, "Expected ordering table in model"
# Compute I the set of tuples (x, y) where
# x -> y does not take a designiated value
I: Set[Tuple[ModelValue, ModelValue]] = set()
@ -167,6 +181,13 @@ def has_vsp(model: Model, impfunction: ModelFunction, mconjunction: Optional[Mod
if bottom is not None and bottom in xs:
continue
# NOTE: Optimization
# If the subalgebras are order-dependent, skip this pair
if order_dependent(xs, ys, model.ordering):
continue
if mnegation is not None and order_dependent(ys, xs, model.ordering):
continue
# Compute the closure of all operations
# with just the xs
carrier_set_left: Set[ModelValue] = model_closure(xs, model.logical_operations, bottom)