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don't 'find' when creating subslice

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This commit is contained in:
Jakob Rath 2023-07-12 16:45:51 +02:00
parent 0fb81fc437
commit 8c17e231ad
3 changed files with 67 additions and 43 deletions
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95
src/math/polysat/slicing.cpp
View file

@ -37,6 +37,34 @@ Recycle the z3 egraph?
- What do we need from the egraph?
- backtracking trail to check for new equalities
(1) x = y
(2) z = y[3:0]
(3) explain(x[3:0] == z)? should be { (1), (2) }
(1)
x ========================> y
/ \ / \ (2)
x[7:4] x[3:0] y[7:4] y[3:0] ===========> z
*/
@ -176,14 +204,6 @@ namespace polysat {
return slice2enode(sub_lo(enode2slice(n)));
}
slicing::slice slicing::find_sub_hi(slice parent) const {
return find(sub_hi(parent));
}
slicing::slice slicing::find_sub_lo(slice parent) const {
return find(sub_lo(parent));
}
// split a single slice without updating any equivalences
void slicing::split_core(slice s, unsigned cut) {
SASSERT(!has_sub(s));
@ -371,17 +391,13 @@ namespace polysat {
slice y = ys.back();
xs.pop_back();
ys.pop_back();
if (x == y) {
// merge upper level?
// but continue loop
}
if (has_sub(x)) {
find_base(x, xs);
get_base(x, xs);
x = xs.back();
xs.pop_back();
}
if (has_sub(y)) {
find_base(y, ys);
get_base(y, ys);
y = ys.back();
ys.pop_back();
}
@ -453,36 +469,41 @@ namespace polysat {
return result;
}
void slicing::find_base(slice src, slice_vector& out_base) const {
// splits are only stored for the representative
SASSERT_EQ(src, find(src));
if (!has_sub(src)) {
out_base.push_back(src);
return;
}
template <bool should_find>
void slicing::get_base_core(slice src, slice_vector& out_base) const {
slice_vector& todo = m_tmp1;
SASSERT(todo.empty());
todo.push_back(src);
while (!todo.empty()) {
slice s = todo.back();
todo.pop_back();
if constexpr (should_find) {
s = find(s);
}
if (!has_sub(s))
out_base.push_back(s);
else {
todo.push_back(find_sub_lo(s));
todo.push_back(find_sub_hi(s));
todo.push_back(sub_lo(s));
todo.push_back(sub_hi(s));
}
}
SASSERT(todo.empty());
}
void slicing::get_base(slice src, slice_vector& out_base) const {
get_base_core<false>(src, out_base);
}
void slicing::find_base(slice src, slice_vector& out_base) const {
get_base_core<true>(src, out_base);
}
void slicing::mk_slice(slice src, unsigned const hi, unsigned const lo, slice_vector& out, bool output_full_src, bool output_base) {
SASSERT(hi >= lo);
SASSERT_EQ(src, find(src)); // splits are only stored for the representative
SASSERT(width(src) > hi); // extracted range must be fully contained inside the src slice
auto output_slice = [this, output_base, &out](slice s) {
if (output_base)
find_base(s, out);
get_base(s, out);
else
out.push_back(s);
};
@ -495,23 +516,23 @@ namespace polysat {
unsigned const cut = m_slice_cut[src];
if (lo >= cut + 1) {
// target slice falls into upper subslice
mk_slice(find_sub_hi(src), hi - cut - 1, lo - cut - 1, out, output_full_src, output_base);
mk_slice(sub_hi(src), hi - cut - 1, lo - cut - 1, out, output_full_src, output_base);
if (output_full_src)
output_slice(find_sub_lo(src));
output_slice(sub_lo(src));
return;
}
else if (cut >= hi) {
// target slice falls into lower subslice
if (output_full_src)
output_slice(find_sub_hi(src));
mk_slice(find_sub_lo(src), hi, lo, out, output_full_src, output_base);
output_slice(sub_hi(src));
mk_slice(sub_lo(src), hi, lo, out, output_full_src, output_base);
return;
}
else {
SASSERT(hi > cut && cut >= lo);
// desired range spans over the cutpoint, so we get multiple slices in the result
mk_slice(find_sub_hi(src), hi - cut - 1, 0, out, output_full_src, output_base);
mk_slice(find_sub_lo(src), cut, lo, out, output_full_src, output_base);
mk_slice(sub_hi(src), hi - cut - 1, 0, out, output_full_src, output_base);
mk_slice(sub_lo(src), cut, lo, out, output_full_src, output_base);
return;
}
}
@ -519,19 +540,19 @@ namespace polysat {
// [src.width-1, 0] has no subdivision yet
if (width(src) - 1 > hi) {
split(src, hi);
SASSERT(!has_sub(find_sub_hi(src)));
SASSERT(!has_sub(sub_hi(src)));
if (output_full_src)
out.push_back(find_sub_hi(src));
mk_slice(find_sub_lo(src), hi, lo, out, output_full_src, output_base); // recursive call to take care of case lo > 0
out.push_back(sub_hi(src));
mk_slice(sub_lo(src), hi, lo, out, output_full_src, output_base); // recursive call to take care of case lo > 0
return;
}
else {
SASSERT(lo > 0);
split(src, lo - 1);
out.push_back(find_sub_hi(src));
SASSERT(!has_sub(find_sub_lo(src)));
out.push_back(sub_hi(src));
SASSERT(!has_sub(sub_lo(src)));
if (output_full_src)
out.push_back(find_sub_lo(src));
out.push_back(sub_lo(src));
return;
}
}

11
src/math/polysat/slicing.h
View file

@ -158,7 +158,12 @@ namespace polysat {
void split(slice s, unsigned cut);
void split_core(slice s, unsigned cut);
/// Retrieve base slices s_1,...,s_n such that src == s_1 ++ ... ++ s_n
template <bool should_find>
void get_base_core(slice src, slice_vector& out_base) const;
/// Retrieve base slices s_1,...,s_n such that src == s_1 ++ ... ++ s_n (actual descendant subslices)
void get_base(slice src, slice_vector& out_base) const;
/// Retrieve base slices s_1,...,s_n such that src == s_1 ++ ... ++ s_n (representatives of subslices)
void find_base(slice src, slice_vector& out_base) const;
/// Retrieve (or create) base slices s_1,...,s_n such that src[hi:lo] == s_1 ++ ... ++ s_n.
/// If output_full_src is true, return the new base for src, i.e., src == s_1 ++ ... ++ s_n.
@ -167,10 +172,6 @@ namespace polysat {
/// Find representative
slice find(slice s) const;
/// Find representative of upper subslice
slice find_sub_hi(slice s) const;
/// Find representative of lower subslice
slice find_sub_lo(slice s) const;
// Merge equivalence classes of two base slices.
// Returns true if merge succeeded without conflict.

4
src/test/slicing.cpp
View file

@ -72,6 +72,8 @@ namespace polysat {
pvar b = sl.mk_extract_var(y, 5, 0);
std::cout << sl << "\n";
sl.display_tree(std::cout);
(void)a;
(void)b;
}
@ -187,7 +189,7 @@ namespace polysat {
void tst_slicing() {
using namespace polysat;
test_slicing::test1();
// test_slicing::test2();
test_slicing::test2();
// test_slicing::test3();
// test_slicing::test4();
// test_slicing::test5();