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Polysat: add simpler monotonicity unit test + minor changes (#5348)

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* Add simpler versions of monotonicity puzzle

* band-aid fix to conflicts during revert_decision

* minor changes
This commit is contained in:
Jakob Rath 2021-06-15 19:18:37 +02:00 • committed by GitHub
parent 9cc78ef98e
commit 1fe7dc40fe
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5 changed files with 135 additions and 32 deletions
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88
src/test/polysat.cpp
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@ -354,15 +354,14 @@ namespace polysat {
*
* We do overflow checks by doubling the base bitwidth here.
*/
static void test_monot() {
static void test_monot(unsigned base_bw = 5) {
scoped_solver s(__func__);
auto baseBw = 5;
auto max_int_const = 31; // (2^5 - 1) -- change this when you change baseBw
auto max_int_const = rational::power_of_two(base_bw) - 1;
auto bw = 2 * baseBw;
unsigned bw = 2 * base_bw;
auto max_int = s.var(s.add_var(bw));
s.add_eq(max_int - max_int_const);
s.add_eq(max_int + (-max_int_const));
auto tb1 = s.var(s.add_var(bw));
s.add_ule(tb1, max_int);
@ -499,11 +498,13 @@ namespace polysat {
s.expect_unsat();
s.pop();
s.push();
s.add_ult(quot3 + em, a);
s.check();
s.expect_unsat();
s.pop();
NOT_IMPLEMENTED_YET(); // this is just a note to continue here once we get the above expect_unsat to pass.
// s.push();
// s.add_ult(quot3 + em, a);
// s.check();
// s.expect_unsat();
// s.pop();
}
/*
@ -579,12 +580,69 @@ namespace polysat {
s.pop();
}
/*
* Transcribed from https://github.com/NikolajBjorner/polysat/blob/main/puzzles/bv.smt2 .
/** Monotonicity under bounds,
* puzzle extracted from https://github.com/NikolajBjorner/polysat/blob/main/puzzles/bv.smt2
*
* x, y, z \in [0..2^64[
* x, y, z < 2^32
* y <= x
* x*z < 2^32
* y*z >= 2^32
*/
static void test_monot_bounds(unsigned base_bw = 32) {
scoped_solver s(__func__);
unsigned bw = 2 * base_bw;
auto x = s.var(s.add_var(bw));
auto y = s.var(s.add_var(bw));
auto z = s.var(s.add_var(bw));
auto zero = x - x;
auto bound = (zero + 2).pow(base_bw);
s.add_ult(x, bound);
s.add_ult(y, bound);
s.add_ult(z, bound);
// TODO: try alternative:
// TODO: maybe we should normalize equations where one side is a constant?
// TODO: should we always express a < b as a <= b - 1 ? [ well, no. this only works if b > 0. ]
// s.add_ule(x, bound - 1);
// s.add_ule(y, bound - 1);
// s.add_ule(z, bound - 1);
s.add_ule(y, x);
s.add_ult(x*z, bound);
s.add_ule(bound, y*z);
s.check();
s.expect_unsat();
}
/** Monotonicity under bounds, simplified even more.
*
* x, y, z \in [0..2^64[
* x, y, z < 2^32
* z <= y
* y*x < z*x
*/
static void test_monot_bounds_simple(unsigned base_bw = 32) {
scoped_solver s(__func__);
unsigned bw = 2 * base_bw;
auto y = s.var(s.add_var(bw));
auto x = s.var(s.add_var(bw));
auto z = s.var(s.add_var(bw));
auto zero = x - x;
auto bound = (zero + 2).pow(base_bw);
s.add_ult(x, bound);
s.add_ult(y, bound);
s.add_ult(z, bound);
s.add_ule(z, y);
s.add_ult(y*x, z*x);
s.check();
s.expect_unsat();
}
/*
* Transcribed from https://github.com/NikolajBjorner/polysat/blob/main/puzzles/bv.smt2
*
* We do overflow checks by doubling the base bitwidth here.
*/
static void test_fixed_point_arith_div_mul_inverse2() {
static void test_monot_bounds_full() {
scoped_solver s(__func__);
auto baseBw = 5;
@ -686,8 +744,10 @@ void tst_polysat() {
polysat::test_ineq_basic4();
polysat::test_ineq_basic5();
polysat::test_ineq_basic6();
polysat::test_fixed_point_arith_div_mul_inverse2();
polysat::test_fixed_point_arith_div_mul_inverse();
polysat::test_monot_bounds_simple(2);
polysat::test_monot_bounds(2);
polysat::test_monot_bounds_full();
polysat::test_fixed_point_arith_mul_div_inverse();
#if 0
// worry about this later