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fix rounding mode for pseudo-boolean constraint creation, Issue #683

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-07-14 12:34:18 -07:00
parent 3a83788b97
commit 4f5b0667ef
3 changed files with 41 additions and 33 deletions
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64
src/ast/pb_decl_plugin.cpp
View file

@ -18,6 +18,7 @@ Revision History:
--*/
#include "pb_decl_plugin.h"
#include "ast_util.h"
pb_decl_plugin::pb_decl_plugin():
m_at_most_sym("at-most"),
@ -99,29 +100,47 @@ void pb_decl_plugin::get_op_names(svector<builtin_name> & op_names, symbol const
}
}
app * pb_util::mk_le(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k) {
vector<parameter> params;
params.push_back(parameter(k));
void pb_util::normalize(unsigned num_args, rational const* coeffs, rational const& k) {
rational d(1);
for (unsigned i = 0; i < num_args; ++i) {
params.push_back(parameter(coeffs[i]));
d = lcm(d, denominator(coeffs[i]));
}
m_coeffs.reset();
for (unsigned i = 0; i < num_args; ++i) {
m_coeffs.push_back(d*coeffs[i]);
}
m_k = d*k;
}
app * pb_util::mk_le(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k) {
normalize(num_args, coeffs, k);
vector<parameter> params;
params.push_back(parameter(floor(m_k)));
for (unsigned i = 0; i < num_args; ++i) {
params.push_back(parameter(m_coeffs[i]));
}
return m.mk_app(m_fid, OP_PB_LE, params.size(), params.c_ptr(), num_args, args, m.mk_bool_sort());
}
app * pb_util::mk_ge(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k) {
normalize(num_args, coeffs, k);
vector<parameter> params;
params.push_back(parameter(k));
params.push_back(parameter(ceil(m_k)));
for (unsigned i = 0; i < num_args; ++i) {
params.push_back(parameter(coeffs[i]));
params.push_back(parameter(m_coeffs[i]));
}
return m.mk_app(m_fid, OP_PB_GE, params.size(), params.c_ptr(), num_args, args, m.mk_bool_sort());
}
app * pb_util::mk_eq(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k) {
normalize(num_args, coeffs, k);
if (!m_k.is_int()) {
return m.mk_false();
}
vector<parameter> params;
params.push_back(parameter(k));
params.push_back(parameter(m_k));
for (unsigned i = 0; i < num_args; ++i) {
params.push_back(parameter(coeffs[i]));
params.push_back(parameter(m_coeffs[i]));
}
return m.mk_app(m_fid, OP_PB_EQ, params.size(), params.c_ptr(), num_args, args, m.mk_bool_sort());
}
@ -132,33 +151,18 @@ app * pb_util::mk_eq(unsigned num_args, rational const * coeffs, expr * const *
// <=>
// a(1-x) + b(1-y) >= -k + a + b + 1
app * pb_util::mk_lt(unsigned num_args, rational const * _coeffs, expr * const * _args, rational const& _k) {
vector<rational> coeffs;
rational k(_k);
normalize(num_args, _coeffs, _k);
expr_ref_vector args(m);
expr* f;
rational d(denominator(k));
for (unsigned i = 0; i < num_args; ++i) {
coeffs.push_back(_coeffs[i]);
d = lcm(d, denominator(coeffs[i]));
if (m.is_not(_args[i], f)) {
args.push_back(f);
}
else {
args.push_back(m.mk_not(_args[i]));
}
args.push_back(mk_not(m, _args[i]));
}
if (!d.is_one()) {
k *= d;
for (unsigned i = 0; i < num_args; ++i) {
coeffs[i] *= d;
}
}
k.neg();
k += rational::one();
m_k = floor(m_k);
m_k.neg();
m_k += rational::one();
for (unsigned i = 0; i < num_args; ++i) {
k += coeffs[i];
m_k += m_coeffs[i];
}
return mk_ge(num_args, coeffs.c_ptr(), args.c_ptr(), k);
return mk_ge(num_args, m_coeffs.c_ptr(), args.c_ptr(), m_k);
}

3
src/ast/pb_decl_plugin.h
View file

@ -79,6 +79,9 @@ public:
class pb_util {
ast_manager & m;
family_id m_fid;
vector<rational> m_coeffs;
rational m_k;
void normalize(unsigned num_args, rational const* coeffs, rational const& k);
public:
pb_util(ast_manager& m):m(m), m_fid(m.mk_family_id("pb")) {}
ast_manager & get_manager() const { return m; }