mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-07 18:05:21 +00:00
Code Activity
z3/lib/old_interval.cpp
Leonardo de Moura e9eab22e5c Z3 sources 
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2012-10-02 11:35:25 -07:00

643 lines
22 KiB
C++
Raw Blame History

/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
old_interval.cpp
Abstract:
<abstract>
Author:
Leonardo de Moura (leonardo) 2008-12-09.
Revision History:
--*/
#include"old_interval.h"
void ext_numeral::neg() {
switch (m_kind) {
case MINUS_INFINITY: m_kind = PLUS_INFINITY; break;
case FINITE: m_value.neg(); break;
case PLUS_INFINITY: m_kind = MINUS_INFINITY; break;
}
}
ext_numeral & ext_numeral::operator+=(ext_numeral const & other) {
SASSERT(!is_infinite() || !other.is_infinite() || m_kind == other.m_kind);
if (is_infinite())
return *this;
SASSERT(m_kind == FINITE);
switch (other.m_kind) {
case MINUS_INFINITY:
m_kind = MINUS_INFINITY;
m_value.reset();
return *this;
case FINITE:
m_value += other.m_value;
return *this;
case PLUS_INFINITY:
m_kind = PLUS_INFINITY;
m_value.reset();
return *this;
}
UNREACHABLE();
return *this;
}
ext_numeral & ext_numeral::operator-=(ext_numeral const & other) {
SASSERT(!is_infinite() || !other.is_infinite() || (m_kind != other.m_kind));
if (is_infinite())
return *this;
SASSERT(m_kind == FINITE);
switch (other.m_kind) {
case MINUS_INFINITY:
m_kind = PLUS_INFINITY;
m_value.reset();
return *this;
case FINITE:
m_value -= other.m_value;
return *this;
case PLUS_INFINITY:
m_kind = MINUS_INFINITY;
m_value.reset();
return *this;
}
UNREACHABLE();
return *this;
}
ext_numeral & ext_numeral::operator*=(ext_numeral const & other) {
if (is_zero() || other.is_zero()) {
m_kind = FINITE;
m_value.reset();
return *this;
}
if (is_infinite() || other.is_infinite()) {
if (sign() == other.sign())
m_kind = PLUS_INFINITY;
else
m_kind = MINUS_INFINITY;
m_value.reset();
return *this;
}
SASSERT(m_kind == FINITE);
m_value *= other.m_value;
return *this;
}
void ext_numeral::expt(unsigned n) {
switch (m_kind) {
case MINUS_INFINITY:
if (n % 2 == 0)
m_kind = PLUS_INFINITY;
return;
case FINITE:
m_value = m_value.expt(n);
break;
case PLUS_INFINITY:
// do nothing
break;
}
}
void ext_numeral::inv() {
SASSERT(!is_zero());
if (is_infinite()) {
m_kind = FINITE;
m_value.reset();
}
else {
m_value = rational(1) / m_value;
}
}
void ext_numeral::display(std::ostream & out) const {
switch (m_kind) {
case MINUS_INFINITY:
out << "-oo";
break;
case FINITE:
out << m_value;
break;
case PLUS_INFINITY:
out << "oo";
break;
}
}
bool operator==(ext_numeral const & n1, ext_numeral const & n2) {
return n1.m_kind == n2.m_kind && (n1.is_infinite() || n1.m_value == n2.m_value);
}
bool operator<(ext_numeral const & n1, ext_numeral const & n2) {
if (n1.is_infinite())
return n1.m_kind == ext_numeral::MINUS_INFINITY && n2.m_kind != ext_numeral::MINUS_INFINITY;
if (n2.is_infinite())
return n2.m_kind != ext_numeral::MINUS_INFINITY;
return n1.m_value < n2.m_value;
}
/**
\brief Create interval (-oo, oo)
*/
interval::interval(v_dependency_manager & m):
m_manager(m),
m_lower(false),
m_upper(true),
m_lower_open(true),
m_upper_open(true),
m_lower_dep(0),
m_upper_dep(0) {
}
/**
\brief Create intervals [l,u], (l,u], [l, u), (l,u), where l and u are numerals.
*/
interval::interval(v_dependency_manager & m, rational const & lower, bool l_open, v_dependency * l_dep, rational const & upper, bool u_open, v_dependency * u_dep):
m_manager(m),
m_lower(lower),
m_upper(upper),
m_lower_open(l_open),
m_upper_open(u_open),
m_lower_dep(l_dep),
m_upper_dep(u_dep) {
SASSERT(lower <= upper);
SASSERT(lower != upper || !l_open || !u_open);
}
/**
\brief Create intervals [l,u], (l,u], [l, u), (l,u), where l and u are ext_numerals.
*/
interval::interval(v_dependency_manager & m, ext_numeral const & lower, bool l_open, v_dependency * l_dep, ext_numeral const & upper, bool u_open, v_dependency * u_dep):
m_manager(m),
m_lower(lower),
m_upper(upper),
m_lower_open(l_open),
m_upper_open(u_open),
m_lower_dep(l_dep),
m_upper_dep(u_dep) {
SASSERT(lower <= upper);
SASSERT(lower != upper || !l_open || !u_open);
}
/**
\brief Create interval [val,val]
*/
interval::interval(v_dependency_manager & m, rational const & val, v_dependency * l_dep, v_dependency * u_dep):
m_manager(m),
m_lower(val),
m_upper(val),
m_lower_open(false),
m_upper_open(false),
m_lower_dep(l_dep),
m_upper_dep(u_dep) {
}
/**
\brief Create intervals (-oo, val], (-oo, val), [val, oo), (val, oo)
*/
interval::interval(v_dependency_manager & m, rational const & val, bool open, bool lower, v_dependency * d):
m_manager(m) {
if (lower) {
m_lower = ext_numeral(val);
m_lower_open = open;
m_lower_dep = d;
m_upper = ext_numeral(true);
m_upper_open = true;
m_upper_dep = 0;
}
else {
m_lower = ext_numeral(false);
m_lower_open = true;
m_lower_dep = 0;
m_upper = ext_numeral(val);
m_upper_open = open;
m_upper_dep = d;
}
}
interval::interval(interval const & other):
m_manager(other.m_manager),
m_lower(other.m_lower),
m_upper(other.m_upper),
m_lower_open(other.m_lower_open),
m_upper_open(other.m_upper_open),
m_lower_dep(other.m_lower_dep),
m_upper_dep(other.m_upper_dep) {
}
interval & interval::operator=(interval const & other) {
m_lower = other.m_lower;
m_upper = other.m_upper;
m_lower_open = other.m_lower_open;
m_upper_open = other.m_upper_open;
m_lower_dep = other.m_lower_dep;
m_upper_dep = other.m_upper_dep;
return *this;
}
interval & interval::operator+=(interval const & other) {
m_lower += other.m_lower;
m_upper += other.m_upper;
m_lower_open |= other.m_lower_open;
m_upper_open |= other.m_upper_open;
m_lower_dep = m_lower.is_infinite() ? 0 : m_manager.mk_join(m_lower_dep, other.m_lower_dep);
m_upper_dep = m_upper.is_infinite() ? 0 : m_manager.mk_join(m_upper_dep, other.m_upper_dep);
return *this;
}
void interval::neg() {
std::swap(m_lower, m_upper);
std::swap(m_lower_open, m_upper_open);
std::swap(m_lower_dep, m_upper_dep);
m_lower.neg();
m_upper.neg();
}
interval & interval::operator-=(interval const & other) {
interval tmp(other);
tmp.neg();
return operator+=(tmp);
}
v_dependency * interval::join(v_dependency * d1, v_dependency * d2, v_dependency * d3, v_dependency * d4) {
return m_manager.mk_join(m_manager.mk_join(d1, d2), m_manager.mk_join(d3,d4));
}
/**
\brief Create a new v_dependency using d1, d2, and (opt1 or opt2).
*/
v_dependency * interval::join_opt(v_dependency * d1, v_dependency * d2, v_dependency * opt1, v_dependency * opt2) {
if (opt1 == d1 || opt1 == d2)
return join(d1, d2);
if (opt2 == d1 || opt2 == d2)
return join(d1, d2);
if (opt1 == 0 || opt2 == 0)
return join(d1, d2);
// TODO: more opts...
return join(d1, d2, opt1);
}
interval & interval::operator*=(interval const & other) {
#if Z3DEBUG || _TRACE
bool contains_zero1 = contains_zero();
bool contains_zero2 = other.contains_zero();
#endif
if (is_zero()) {
return *this;
}
if (other.is_zero()) {
*this = other;
return *this;
}
ext_numeral const & a = m_lower;
ext_numeral const & b = m_upper;
ext_numeral const & c = other.m_lower;
ext_numeral const & d = other.m_upper;
bool a_o = m_lower_open;
bool b_o = m_upper_open;
bool c_o = other.m_lower_open;
bool d_o = other.m_upper_open;
v_dependency * a_d = m_lower_dep;
v_dependency * b_d = m_upper_dep;
v_dependency * c_d = other.m_lower_dep;
v_dependency * d_d = other.m_upper_dep;
TRACE("interval_bug", tout << "operator*= " << *this << " " << other << "\n";);
if (is_N()) {
if (other.is_N()) {
// x <= b <= 0, y <= d <= 0 --> b*d <= x*y
// a <= x <= b <= 0, c <= y <= d <= 0 --> x*y <= a*c (we can use the fact that x or y is always negative (i.e., b is neg or d is neg))
TRACE("interval_bug", tout << "(N, N)\n";);
ext_numeral new_lower = b * d;
ext_numeral new_upper = a * c;
// if b = 0 (and the interval is closed), then the lower bound is closed
m_lower_open = (is_N0() || other.is_N0()) ? false : (b_o || d_o);
m_upper_open = a_o || c_o; SASSERT(a.is_neg() && c.is_neg());
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(b_d, d_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join_opt(a_d, c_d, b_d, d_d);
}
else if (other.is_M()) {
// a <= x <= b <= 0, y <= d, d > 0 --> a*d <= x*y (uses the fact that b is not positive)
// a <= x <= b <= 0, c <= y, c < 0 --> x*y <= a*c (uses the fact that b is not positive)
TRACE("interval_bug", tout << "(N, M)\n";);
ext_numeral new_lower = a * d; SASSERT(new_lower.is_neg());
ext_numeral new_upper = a * c; SASSERT(new_upper.is_pos());
m_lower_open = a_o || d_o;
m_upper_open = a_o || c_o;
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(a_d, d_d, b_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(a_d, c_d, b_d);
}
else {
// a <= x <= b <= 0, 0 <= c <= y <= d --> a*d <= x*y (uses the fact that x is neg (b is not positive) or y is pos (c is not negative))
// x <= b <= 0, 0 <= c <= y --> x*y <= b*c
TRACE("interval_bug", tout << "(N, P)\n";);
SASSERT(other.is_P());
ext_numeral new_lower = a * d;
ext_numeral new_upper = b * c;
bool is_N0_old = is_N0(); // see comment in (P, N) case
m_lower_open = a_o || d_o; SASSERT(a.is_neg() && d.is_pos());
m_upper_open = (is_N0_old || other.is_P0()) ? false : (b_o || c_o);
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join_opt(a_d, d_d, b_d, c_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(b_d, c_d);
}
}
else if (is_M()) {
if (other.is_N()) {
// b > 0, x <= b, c <= y <= d <= 0 --> b*c <= x*y (uses the fact that d is not positive)
// a < 0, a <= x, c <= y <= d <= 0 --> x*y <= a*c (uses the fact that d is not positive)
TRACE("interval_bug", tout << "(M, N)\n";);
ext_numeral new_lower = b * c; SASSERT(new_lower.is_neg());
ext_numeral new_upper = a * c; SASSERT(new_upper.is_pos());
m_lower_open = b_o || c_o; SASSERT(b.is_pos() && c.is_neg());
m_upper_open = a_o || c_o; SASSERT(a.is_neg() && c.is_neg());
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(b_d, c_d, d_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(a_d, c_d, d_d);
}
else if (other.is_M()) {
TRACE("interval_bug", tout << "(M, M)\n";);
SASSERT(!a.is_zero() && !b.is_zero() && !c.is_zero() && !d.is_zero());
ext_numeral ad = a*d; SASSERT(!ad.is_zero());
ext_numeral bc = b*c; SASSERT(!bc.is_zero());
ext_numeral ac = a*c; SASSERT(!ac.is_zero());
ext_numeral bd = b*d; SASSERT(!bd.is_zero());
bool ad_o = a_o || d_o;
bool bc_o = b_o || c_o;
bool ac_o = a_o || c_o;
bool bd_o = b_o || d_o;
if (ad < bc || (ad == bc && !ad_o && bc_o)) {
m_lower = ad;
m_lower_open = ad_o;
}
else {
m_lower = bc;
m_lower_open = bc_o;
}
if (ac > bd || (ac == bd && !ac_o && bd_o)) {
m_upper = ac;
m_upper_open = ac_o;
}
else {
m_upper = bd;
m_upper_open = bd_o;
}
m_lower_dep = m_lower.is_infinite() ? 0 : join(a_d, b_d, c_d, d_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(a_d, b_d, c_d, d_d);
}
else {
// a < 0, a <= x, 0 <= c <= y <= d --> a*d <= x*y (uses the fact that c is not negative)
// b > 0, x <= b, 0 <= c <= y <= d --> x*y <= b*d (uses the fact that c is not negative)
TRACE("interval_bug", tout << "(M, P)\n";);
SASSERT(other.is_P());
ext_numeral new_lower = a * d; SASSERT(new_lower.is_neg());
ext_numeral new_upper = b * d; SASSERT(new_upper.is_pos());
m_lower_open = a_o || d_o; SASSERT(a.is_neg() && d.is_pos());
m_upper_open = b_o || d_o; SASSERT(b.is_pos() && d.is_pos());
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(a_d, d_d, c_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(b_d, d_d, c_d);
}
}
else {
SASSERT(is_P());
if (other.is_N()) {
// 0 <= a <= x <= b, c <= y <= d <= 0 --> x*y <= b*c (uses the fact that x is pos (a is not neg) or y is neg (d is not pos))
// 0 <= a <= x, y <= d <= 0 --> a*d <= x*y
TRACE("interval_bug", tout << "(P, N)\n";);
ext_numeral new_lower = b * c;
ext_numeral new_upper = a * d;
bool is_P0_old = is_P0(); // cache the value of is_P0(), since it may be affected by the next update.
m_lower_open = b_o || c_o; SASSERT(b.is_pos() && c.is_neg());
m_upper_open = (is_P0_old || other.is_N0()) ? false : a_o || d_o;
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join_opt(b_d, c_d, a_d, d_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(a_d, d_d);
}
else if (other.is_M()) {
// 0 <= a <= x <= b, c <= y --> b*c <= x*y (uses the fact that a is not negative)
// 0 <= a <= x <= b, y <= d --> x*y <= b*d (uses the fact that a is not negative)
TRACE("interval_bug", tout << "(P, M)\n";);
ext_numeral new_lower = b * c; SASSERT(new_lower.is_neg());
ext_numeral new_upper = b * d; SASSERT(new_upper.is_pos());
m_lower_open = b_o || c_o;
m_upper_open = b_o || d_o;
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(b_d, c_d, a_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join(b_d, d_d, a_d);
}
else {
// 0 <= a <= x, 0 <= c <= y --> a*c <= x*y
// x <= b, y <= d --> x*y <= b*d (uses the fact that x is pos (a is not negative) or y is pos (c is not negative))
TRACE("interval_bug", tout << "(P, P)\n";);
SASSERT(other.is_P());
ext_numeral new_lower = a * c;
ext_numeral new_upper = b * d;
m_lower_open = (is_P0() || other.is_P0()) ? false : a_o || c_o;
m_upper_open = b_o || d_o; SASSERT(b.is_pos() && d.is_pos());
m_lower = new_lower;
m_upper = new_upper;
m_lower_dep = m_lower.is_infinite() ? 0 : join(a_d, c_d);
m_upper_dep = m_upper.is_infinite() ? 0 : join_opt(b_d, d_d, a_d, c_d);
}
}
TRACE("interval_bug", tout << "operator*= result: " << *this << "\n";);
CTRACE("interval", !(!(contains_zero1 || contains_zero2) || contains_zero()),
tout << "contains_zero1: " << contains_zero1 << ", contains_zero2: " << contains_zero2 << ", contains_zero(): " << contains_zero() << "\n";);
SASSERT(!(contains_zero1 || contains_zero2) || contains_zero());
return *this;
}
bool interval::contains_zero() const {
TRACE("interval_zero_bug", tout << "contains_zero info: " << *this << "\n";
tout << "m_lower.is_neg(): " << m_lower.is_neg() << "\n";
tout << "m_lower.is_zero: " << m_lower.is_zero() << "\n";
tout << "m_lower_open: " << m_lower_open << "\n";
tout << "m_upper.is_pos(): " << m_upper.is_pos() << "\n";
tout << "m_upper.is_zero: " << m_upper.is_zero() << "\n";
tout << "m_upper_open: " << m_upper_open << "\n";
tout << "result: " << ((m_lower.is_neg() || (m_lower.is_zero() && !m_lower_open)) && (m_upper.is_pos() || (m_upper.is_zero() && !m_upper_open))) << "\n";);
return
(m_lower.is_neg() || (m_lower.is_zero() && !m_lower_open)) &&
(m_upper.is_pos() || (m_upper.is_zero() && !m_upper_open));
}
bool interval::contains(rational const& v) const {
if (!inf().is_infinite()) {
if (v < inf().to_rational()) return false;
if (v == inf().to_rational() && m_lower_open) return false;
}
if (!sup().is_infinite()) {
if (v > sup().to_rational()) return false;
if (v == sup().to_rational() && m_upper_open) return false;
}
return true;
}
interval & interval::inv() {
// If the interval [l,u] does not contain 0, then 1/[l,u] = [1/u, 1/l]
SASSERT(!contains_zero());
if (is_P1()) {
// 0 < a <= x --> 1/x <= 1/a
// 0 < a <= x <= b --> 1/b <= 1/x (use lower and upper bounds)
ext_numeral new_lower = m_upper; SASSERT(!m_upper.is_zero());
new_lower.inv();
ext_numeral new_upper;
if (m_lower.is_zero()) {
SASSERT(m_lower_open);
ext_numeral plus_infinity(true);
new_upper = plus_infinity;
}
else {
new_upper = m_lower;
new_upper.inv();
}
m_lower = new_lower;
m_upper = new_upper;
std::swap(m_lower_open, m_upper_open);
v_dependency * new_upper_dep = m_lower_dep;
SASSERT(!m_lower.is_infinite());
m_lower_dep = m_manager.mk_join(m_lower_dep, m_upper_dep);
m_upper_dep = new_upper_dep;
}
else if (is_N1()) {
// x <= a < 0 --> 1/a <= 1/x
// b <= x <= a < 0 --> 1/b <= 1/x (use lower and upper bounds)
ext_numeral new_upper = m_lower; SASSERT(!m_lower.is_zero());
new_upper.inv();
ext_numeral new_lower;
if (m_upper.is_zero()) {
SASSERT(m_upper_open);
ext_numeral minus_infinity(false);
new_lower = minus_infinity;
}
else {
new_lower = m_upper;
new_lower.inv();
}
m_lower = new_lower;
m_upper = new_upper;
std::swap(m_lower_open, m_upper_open);
v_dependency * new_lower_dep = m_upper_dep;
SASSERT(!m_upper.is_infinite());
m_upper_dep = m_manager.mk_join(m_lower_dep, m_upper_dep);
m_lower_dep = new_lower_dep;
}
else {
UNREACHABLE();
}
return *this;
}
interval & interval::operator/=(interval const & other) {
SASSERT(!other.contains_zero());
if (is_zero()) {
// 0/other = 0 if other != 0
TRACE("interval", other.display_with_dependencies(tout););
if (other.m_lower.is_pos() || (other.m_lower.is_zero() && other.m_lower_open)) {
// other.lower > 0
m_lower_dep = join(m_lower_dep, other.m_lower_dep);
m_upper_dep = join(m_upper_dep, other.m_lower_dep);
}
else {
// assertion must hold since !other.contains_zero()
SASSERT(other.m_upper.is_neg() || (other.m_upper.is_zero() && other.m_upper_open));
// other.upper < 0
m_lower_dep = join(m_lower_dep, other.m_upper_dep);
m_upper_dep = join(m_upper_dep, other.m_upper_dep);
}
return *this;
}
else {
interval tmp(other);
tmp.inv();
return operator*=(tmp);
}
}
void interval::expt(unsigned n) {
if (n == 1)
return;
if (n % 2 == 0) {
if (m_lower.is_pos()) {
// [l, u]^n = [l^n, u^n] if l > 0
// 0 < a <= x --> a^n <= x^n (lower bound guarantees that is positive)
// 0 < a <= x <= b --> x^n <= b^n (use lower and upper bound -- need the fact that x is positive)
m_lower.expt(n);
m_upper.expt(n);
m_upper_dep = m_upper.is_infinite() ? 0 : m_manager.mk_join(m_lower_dep, m_upper_dep);
}
else if (m_upper.is_neg()) {
// [l, u]^n = [u^n, l^n] if u < 0
// a <= x <= b < 0 --> x^n <= a^n (use lower and upper bound -- need the fact that x is negative)
// x <= b < 0 --> b^n <= x^n
std::swap(m_lower, m_upper);
std::swap(m_lower_open, m_upper_open);
std::swap(m_lower_dep, m_upper_dep);
m_lower.expt(n);
m_upper.expt(n);
m_upper_dep = m_upper.is_infinite() ? 0 : m_manager.mk_join(m_lower_dep, m_upper_dep);
}
else {
// [l, u]^n = [0, max{l^n, u^n}] otherwise
// we need both bounds to justify upper bound
TRACE("interval", tout << "before: " << m_lower << " " << m_upper << " " << n << "\n";);
m_lower.expt(n);
m_upper.expt(n);
TRACE("interval", tout << "after: " << m_lower << " " << m_upper << "\n";);
if (m_lower > m_upper || (m_lower == m_upper && !m_lower_open && m_upper_open)) {
m_upper = m_lower;
m_upper_open = m_lower_open;
}
m_upper_dep = m_upper.is_infinite() ? 0 : m_manager.mk_join(m_lower_dep, m_upper_dep);
m_lower = ext_numeral(0);
m_lower_open = false;
m_lower_dep = 0;
}
}
else {
// Remark: when n is odd x^n is monotonic.
m_lower.expt(n);
m_upper.expt(n);
}
}
void interval::display(std::ostream & out) const {
out << (m_lower_open ? "(" : "[") << m_lower << ", " << m_upper << (m_upper_open ? ")" : "]");
}
void interval::display_with_dependencies(std::ostream & out) const {
ptr_vector<void> vs;
m_manager.linearize(m_lower_dep, vs);
m_manager.linearize(m_upper_dep, vs);
out << "[";
display(out);
out << ", ";
bool first = true;
::display(out, vs.begin(), vs.end(), ", ", first);
out << "]";
}
View git blame Copy permalink