mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-11-04 05:19:11 +00:00
Code Activity

Update viable::propagate_from_containing_slice to use new get_fixed_sub_slices (wip)

Browse source
This commit is contained in:
Jakob Rath 2024-02-07 17:16:26 +01:00
parent 9283b4169c
commit 85d3e266a4
2 changed files with 171 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

184
src/sat/smt/polysat/viable.cpp
View file

@ -645,18 +645,36 @@ namespace polysat {
return result;
}
dependency viable::propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps) {
for (auto const& slice : m_overlaps)
if (auto d = propagate_from_containing_slice(e, value, e_deps, slice); !d.is_null())
dependency viable::propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps) {
verbose_stream() << "\n\n\n\n\n\nNon-viable assignment for v" << m_var << " size " << c.size(m_var) << "\n";
display_one(verbose_stream() << "entry: ", e) << "\n";
verbose_stream() << "value " << value << "\n";
fixed_slice_extra_vector fixed;
offset_slice_extra_vector subslices;
#if 0
verbose_stream() << "fixed subslices of v" << m_var << ":\n";
c.s.get_fixed_sub_slices(m_var, fixed, subslices); // TODO: move into m_fixed bits?
// TODO: the conflict should be from the subslice with highest level. we might want to skip the others.
for (auto const& slice : subslices)
if (auto d = propagate_from_containing_slice(e, value, e_deps, fixed, slice); !d.is_null())
return d;
#else
for (auto const& slice : m_overlaps)
if (auto d = propagate_from_containing_slice(e, value, e_deps, fixed, {slice.v, slice.offset, 0}); !d.is_null())
return d;
#endif
return null_dependency;
}
dependency viable::propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps, offset_slice const& slice) {
auto [w, offset] = slice;
dependency viable::propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps, fixed_slice_extra_vector const& fixed, offset_slice_extra const& slice) {
pvar w = slice.v;
unsigned offset = slice.offset;
unsigned w_level = slice.level; // level where value of w was fixed
if (w == m_var)
return null_dependency;
verbose_stream() << "v" << m_var << " size " << c.size(m_var) << ", v" << w << " size " << c.size(w) << " offset " << offset << "\n";
verbose_stream() << "v" << m_var << " size " << c.size(m_var) << ", v" << w << " size " << c.size(w) << " offset " << offset << " level " << w_level << "\n";
// Let:
// v = m_var[e->bit_width-1:0]
@ -685,12 +703,8 @@ namespace polysat {
unsigned const z_sz = offset;
unsigned const y_sz = std::min(w_sz, v_sz - z_sz);
unsigned const x_sz = v_sz - y_sz;
rational const& w_shift = rational::power_of_two(w_sz - y_sz);
verbose_stream() << "v_sz " << v_sz << " w_sz " << w_sz << " / x_sz " << x_sz << " y_sz " << y_sz << " z_sz " << z_sz << "\n";
display_one(verbose_stream() << "entry: ", e) << "\n";
verbose_stream() << "value " << value << "\n";
SASSERT(!e->interval.is_full());
rational const& lo = e->interval.lo_val();
@ -699,6 +713,147 @@ namespace polysat {
r_interval const v_ivl = r_interval::proper(lo, hi);
verbose_stream() << "propagate interval " << v_ivl << " from v" << m_var << " to v" << w << "[" << y_sz << "]" << "\n";
#if 0
dependency_vector deps;
deps.append(e_deps); // explains e
deps.push_back(offset_claim{m_var, slice}); // explains m_var[...] = w
r_interval ivl = v_ivl;
// chop off x-part, taking fixed values into account whenever possible.
unsigned const x_off = y_sz + z_sz;
unsigned remaining_x_sz = x_sz;
while (remaining_x_sz > 0 && !ivl.is_empty() && !ivl.is_full()) {
unsigned remaining_x_end = remaining_x_sz + x_off;
// find next fixed slice (prefer lower level)
fixed_slice_extra best;
unsigned best_end = 0;
SASSERT(best_end < x_off); // because y_sz != 0
for (auto const& f : fixed) {
if (f.level >= w_level)
continue;
// ??????xxxxxxxyyyyyyzzzz
// 1111 not useful at this point
// 11111 OK
// 1111 OK (has gap without fixed value)
// 1111 NOT OK (overlaps y) ... although, why would that not be ok? it just restricts values of y too. maybe this can be used to improve interval for y further.
// 111111 not useful at this point
if (f.offset >= remaining_x_end)
continue;
if (f.end() <= x_off)
continue;
unsigned const f_end = std::min(remaining_x_end, f.end()); // for comparison, values beyond the current range don't matter
if (f_end > best_end)
best = f, best_end = f_end;
else if (f_end == best_end && f.level < best.level)
best = f, best_end = f_end;
}
if (best_end < remaining_x_end) {
// there is a gap without a fixed value
unsigned const b = std::max(best_end, x_off);
unsigned const a = remaining_x_end - b;
SASSERT(remaining_x_sz >= a);
ivl = chop_off_upper(ivl, a, b);
remaining_x_sz -= a;
remaining_x_end -= a;
}
if (best_end > x_off) {
verbose_stream() << " using fixed slice " << best.value << "[" << best.length << "]@" << best.offset << "\n";
SASSERT(remaining_x_end == best_end);
SASSERT(remaining_x_end <= best.end());
// chop off portion with fixed value
unsigned const b = std::max(x_off, best.offset);
unsigned const a = remaining_x_end - b;
rational value = best.value;
if (b > best.offset)
value = machine_div2k(value, b - best.offset);
value = mod2k(value, a);
ivl = chop_off_upper(ivl, a, b, &value);
remaining_x_sz -= a;
remaining_x_end -= a;
deps.push_back(best.dep); // justification for the fixed value
}
}
if (ivl.is_empty())
return null_dependency;
// chop off z-part
unsigned remaining_z_sz = z_sz;
while (remaining_z_sz > 0 && !ivl.is_empty() && !ivl.is_full()) {
SASSERT(remaining_x_sz == 0);
unsigned remaining_z_off = z_sz - remaining_z_sz;
// find next fixed slice (prefer lower level)
fixed_slice_extra best;
unsigned best_off = UINT_MAX;
for (auto const& f : fixed) {
if (f.level >= w_level)
continue;
// ?????????????yyyyyyzzzzz???
// 1111 not useful at this point
// 1111 OK
// 1111 OK (has gap without fixed value)
// 111 not useful
if (f.offset >= z_sz)
continue;
if (f.end() <= remaining_z_off)
continue;
unsigned const f_off = std::max(remaining_z_off, f.offset); // for comparison, values beyond the current range don't matter
if (f_off < best_off)
best = f, best_off = f_off;
else if (f_off == best_off && f.level < best.level)
best = f, best_off = f_off;
}
if (best_off > remaining_z_off) {
// there is a gap without a fixed value
unsigned const b = best_off - remaining_z_off;
unsigned const a = y_sz + z_sz - b;
SASSERT(remaining_x_sz >= a);
ivl = chop_off_lower(ivl, a, b);
remaining_z_sz -= b;
remaining_z_off += b;
}
if (best_off < z_sz) {
verbose_stream() << " using fixed slice " << best.value << "[" << best.length << "]@" << best.offset << "\n";
SASSERT_EQ(best_off, remaining_z_off);
unsigned const b = std::min(best.end(), z_sz) - remaining_z_off;
unsigned const a = y_sz + z_sz - b;
rational value = best.value;
if (best.offset < best_off)
value = machine_div2k(value, best_off - best.offset);
value = mod2k(value, b);
ivl = chop_off_lower(ivl, a, b, &value);
remaining_z_sz -= b;
remaining_z_off += b;
deps.push_back(best.dep); // justification for the fixed value
}
}
if (ivl.is_empty())
return null_dependency;
verbose_stream() << "=> v" << w << "[" << y_sz << "] not in " << ivl << "\n"; // << " using x=" << x_value << " z=" << z_value << "\n";
if (ivl.is_full()) {
// TODO: set conflict
NOT_IMPLEMENTED_YET();
}
else {
// proper interval
auto sc = ~cs.ult(w_shift * (c.var(w) - ivl.lo()), w_shift * (ivl.hi() - ivl.lo()));
return c.propagate(sc, deps, "propagate from containing slice");
}
#else
// TODO: by the time we call viable::assign, m_fixed_bits only contains a single slice with 'value'.
// if we had access to the actually fixed slices (not just fixed because of the latest assignment),
// we could chop off fixed and non-fixed parts according to actually fixed slices;
@ -762,13 +917,14 @@ namespace polysat {
// y is unconstrained, nothing to do here
}
}
#endif
return null_dependency;
}
/// Let x = concat(y, z) and x \not\in [lo;hi[.
/// Returns an interval I such that z \not\in I.
/// Let x = concat(y, z) and x not in [lo;hi[.
/// Returns an interval I such that z not in I.
r_interval viable::chop_off_upper(r_interval const& i, unsigned const Ny, unsigned const Nz, rational const* y_fixed_value) {
if (i.is_full())
return r_interval::full();
@ -804,8 +960,8 @@ namespace polysat {
UNREACHABLE();
}
/// Let x = concat(y, z) and x \not\in [lo;hi[.
/// Returns an interval I such that y \not\in I.
/// Let x = concat(y, z) and x not in [lo;hi[.
/// Returns an interval I such that y not in I.
r_interval viable::chop_off_lower(r_interval const& i, unsigned const Ny, unsigned const Nz, rational const* z_fixed_value) {
if (i.is_full())
return r_interval::full();

3
src/sat/smt/polysat/viable.h
View file

@ -116,13 +116,12 @@ namespace polysat {
bool intersect(pvar v, entry* e);
dependency propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps);
dependency propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps, offset_slice const& slice);
dependency propagate_from_containing_slice(entry* e, rational const& value, dependency_vector const& e_deps, fixed_slice_extra_vector const& fixed, offset_slice_extra const& slice);
static r_interval chop_off_upper(r_interval const& i, unsigned Ny, unsigned Nz, rational const* y_fixed_value = nullptr);
static r_interval chop_off_lower(r_interval const& i, unsigned Ny, unsigned Nz, rational const* z_fixed_value = nullptr);
// find the first non-fixed entry that overlaps with val, if any.
entry* find_overlap(rational& val);
entry* find_overlap(pvar w, rational& val);
entry* find_overlap(pvar w, layer& l, rational const& val);
void update_value_to_high(rational& val, entry* e);