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disable unsound simplification of root objects, and incorrect evaluation of negative even roots

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2015-12-09 08:41:59 -08:00
parent 8949790c16
commit 035f2bb0da
4 changed files with 31 additions and 17 deletions
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16
src/tactic/arith/purify_arith_tactic.cpp
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@ -347,7 +347,7 @@ struct purify_arith_proc {
expr * x = args[0];
expr * zero = u().mk_numeral(rational(0), is_int);
expr * one = u().mk_numeral(rational(1), is_int);
if (y.is_zero()) {
if (y.is_zero() && complete()) {
// (^ x 0) --> k | x != 0 implies k = 1, x = 0 implies k = 0^0
push_cnstr(OR(EQ(x, zero), EQ(k, one)));
push_cnstr_pr(result_pr);
@ -366,7 +366,7 @@ struct purify_arith_proc {
push_cnstr(EQ(x, u().mk_power(k, u().mk_numeral(n, false))));
push_cnstr_pr(result_pr);
}
else {
else if (complete()) {
SASSERT(n.is_even());
// (^ x (/ 1 n)) --> k | x >= 0 implies (x = k^n and k >= 0), x < 0 implies k = neg-root(x, n)
// when n is even
@ -374,11 +374,13 @@ struct purify_arith_proc {
AND(EQ(x, u().mk_power(k, u().mk_numeral(n, false))),
u().mk_ge(k, zero))));
push_cnstr_pr(result_pr);
if (complete()) {
push_cnstr(OR(u().mk_ge(x, zero),
EQ(k, u().mk_neg_root(x, u().mk_numeral(n, false)))));
push_cnstr_pr(result_pr);
}
push_cnstr(OR(u().mk_ge(x, zero),
EQ(k, u().mk_neg_root(x, u().mk_numeral(n, false)))));
push_cnstr_pr(result_pr);
}
else {
return BR_FAILED;
}
}
else {