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Forward propagation for op_constraints + optimization for left/right shift

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This commit is contained in:
Clemens Eisenhofer 2023-01-11 10:29:26 +01:00
parent 1d0ad1ccc0
commit 2581754c3e
4 changed files with 89 additions and 45 deletions
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25
src/math/polysat/variable_elimination.cpp
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@ -684,8 +684,7 @@ namespace polysat {
//return { p, false, {} };
LOG("Warning: Inverting " << a << " although it is not a single variable - might not be a good idea");
}
#if 1
unsigned a_parity;
if ((a_parity = saturation.min_parity(a)) != saturation.max_parity(a) || saturation.min_parity(a1) < a_parity)
return { p, false }; // We need the parity of a and this has to be for sure less than the parity of a1
@ -699,6 +698,7 @@ namespace polysat {
pdd a_pi = s.pseudo_inv(a);
//precondition.insert_eval(~s.eq(a_pi * a, rational::power_of_two(a_parity))); // TODO: This is unfortunately not a justification as the inverse might not be set yet (Can we make it to one?)
precondition.insert_eval(~s.parity_at_most(a, a_parity));
verbose_stream() << "parity at most: " << ~s.parity_at_most(a, a_parity) << "\n";
#endif
pdd shift = a;
@ -716,27 +716,6 @@ namespace polysat {
LOG("shifted a" << shift);
LOG("Forced elimination: " << a_pi * (-b) * shift + b1);
return { a_pi * (-b) * shift + b1, true };
#else
unsigned a_parity;
unsigned a1_parity;
if ((a_parity = saturation.min_parity(a)) != saturation.max_parity(a) || (a1_parity = saturation.min_parity(a1)) != saturation.max_parity(a1))
return { p, false }; // We need the parity, but we failed to get it precisely
if (a_parity > a1_parity) {
SASSERT(false); // get_multiple should have excluded this case already
return { p, false };
}
auto odd_a = get_odd(a, a_parity, precondition);
auto odd_a1 = get_odd(a1, a1_parity, precondition);
pdd inv_odd_a = get_inverse(odd_a);
LOG("Forced elimination: " << odd_a1 * inv_odd_a * rational::power_of_two(a1_parity - a_parity) * b + b1);
verbose_stream() << "Forced elimination: " << odd_a1 * inv_odd_a * rational::power_of_two(a1_parity - a_parity) * (-b) + b1 << "\n";
verbose_stream() << "From: " << "eliminated v" << x << " with a = " << a << "; -b = " << -b << "; p = " << p << "\n";
return { odd_a1 * inv_odd_a * rational::power_of_two(a1_parity - a_parity) * (-b) + b1, true };
#endif
#endif
}
}