diff --git a/src/ast/rewriter/arith_rewriter.cpp b/src/ast/rewriter/arith_rewriter.cpp index 7cade3bfa..ed36562ca 100644 --- a/src/ast/rewriter/arith_rewriter.cpp +++ b/src/ast/rewriter/arith_rewriter.cpp @@ -16,6 +16,7 @@ Author: Notes: --*/ + #include "params/arith_rewriter_params.hpp" #include "ast/rewriter/arith_rewriter.h" #include "ast/rewriter/poly_rewriter_def.h" @@ -1046,19 +1047,21 @@ br_status arith_rewriter::mk_idiv_core(expr * arg1, expr * arg2, expr_ref & resu set_curr_sort(arg1->get_sort()); numeral v1, v2; bool is_int; - if (m_util.is_numeral(arg1, v1, is_int) && m_util.is_numeral(arg2, v2, is_int) && !v2.is_zero()) { + bool is_num1 = m_util.is_numeral(arg1, v1, is_int); + bool is_num2 = m_util.is_numeral(arg2, v2, is_int); + if (is_num1 && is_num2 && !v2.is_zero()) { result = m_util.mk_numeral(div(v1, v2), is_int); return BR_DONE; } - if (m_util.is_numeral(arg2, v2, is_int) && v2.is_one()) { + if (is_num2 && v2.is_one()) { result = arg1; return BR_DONE; } - if (m_util.is_numeral(arg2, v2, is_int) && v2.is_minus_one()) { + if (is_num2 && v2.is_minus_one()) { result = m_util.mk_mul(m_util.mk_int(-1), arg1); return BR_REWRITE1; } - if (m_util.is_numeral(arg2, v2, is_int) && v2.is_zero()) { + if (is_num2 && v2.is_zero()) { return BR_FAILED; } if (arg1 == arg2) { @@ -1066,7 +1069,7 @@ br_status arith_rewriter::mk_idiv_core(expr * arg1, expr * arg2, expr_ref & resu result = m.mk_ite(m.mk_eq(arg1, zero), m_util.mk_idiv(zero, zero), m_util.mk_int(1)); return BR_REWRITE3; } - if (m_util.is_numeral(arg2, v2, is_int) && v2.is_pos() && m_util.is_add(arg1)) { + if (is_num2 && v2.is_pos() && m_util.is_add(arg1)) { expr_ref_buffer args(m); bool change = false; rational add(0); @@ -1092,7 +1095,14 @@ br_status arith_rewriter::mk_idiv_core(expr * arg1, expr * arg2, expr_ref & resu expr_ref zero(m_util.mk_int(0), m); result = m.mk_ite(m.mk_eq(zero, arg2), m_util.mk_idiv(arg1, zero), result); return BR_REWRITE_FULL; - } + } +#if 0 + expr* x = nullptr, *y = nullptr, *z = nullptr; + if (is_num2 && m_util.is_idiv(arg1, x, y) && m_util.is_numeral(y, v1) && v1 > 0 && v2 > 0) { + result = m_util.mk_idiv(x, m_util.mk_numeral(v1*v2, is_int)); + return BR_DONE; + } +#endif return BR_FAILED; } diff --git a/src/math/lp/gomory.cpp b/src/math/lp/gomory.cpp index 2d187c9f4..8c86e0989 100644 --- a/src/math/lp/gomory.cpp +++ b/src/math/lp/gomory.cpp @@ -377,10 +377,20 @@ bool gomory::is_gomory_cut_target(const row_strip& row) { } int gomory::find_basic_var() { - int result = -1; unsigned n = 0; + int result = -1; unsigned min_row_size = UINT_MAX; - // Prefer smaller row size + +#if 0 + result = lia.select_int_infeasible_var(); + + if (result == -1) + return result; + + const row_strip& row = lra.get_row(lia.row_of_basic_column(result)); + if (is_gomory_cut_target(row)) + return result; +#endif for (unsigned j : lra.r_basis()) { if (!lia.column_is_int_inf(j)) @@ -389,6 +399,7 @@ int gomory::find_basic_var() { if (!is_gomory_cut_target(row)) continue; IF_VERBOSE(20, lia.display_row_info(verbose_stream(), lia.row_of_basic_column(j))); + // Prefer smaller row size if (min_row_size == UINT_MAX || 2*row.size() < min_row_size || (4*row.size() < 5*min_row_size && lia.random() % (++n) == 0)) { diff --git a/src/math/lp/int_branch.cpp b/src/math/lp/int_branch.cpp index fc7b5c3ec..da34f77fd 100644 --- a/src/math/lp/int_branch.cpp +++ b/src/math/lp/int_branch.cpp @@ -52,16 +52,22 @@ lia_move int_branch::create_branch_on_column(int j) { int int_branch::find_inf_int_base_column() { + +#if 0 + return lia.select_int_infeasible_var(); +#endif + int result = -1; mpq range; mpq new_range; - mpq small_range_thresold(1024); + mpq small_value(1024); unsigned n = 0; lar_core_solver & lcs = lra.m_mpq_lar_core_solver; unsigned prev_usage = 0; // to quiet down the compile unsigned k = 0; unsigned usage; unsigned j; + // this loop looks for a column with the most usages, but breaks when // a column with a small span of bounds is found for (; k < lra.r_basis().size(); k++) { @@ -69,12 +75,13 @@ int int_branch::find_inf_int_base_column() { if (!lia.column_is_int_inf(j)) continue; usage = lra.usage_in_terms(j); - if (lia.is_boxed(j) && (range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(2*usage)) <= small_range_thresold) { + if (lia.is_boxed(j) && (range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(2*usage)) <= small_value) { result = j; k++; n = 1; break; } + if (n == 0 || usage > prev_usage) { result = j; prev_usage = usage; diff --git a/src/math/lp/int_solver.cpp b/src/math/lp/int_solver.cpp index e338e222a..6c34ce16f 100644 --- a/src/math/lp/int_solver.cpp +++ b/src/math/lp/int_solver.cpp @@ -632,4 +632,73 @@ bool int_solver::non_basic_columns_are_at_bounds() const { return true; } +int int_solver::select_int_infeasible_var() { + int result = -1; + mpq range; + mpq new_range; + mpq small_value(1024); + unsigned n = 0; + lar_core_solver & lcs = lra.m_mpq_lar_core_solver; + unsigned prev_usage = 0; // to quiet down the compile + unsigned k = 0; + unsigned usage; + unsigned j; + + enum state { small_box, is_small_value, any_value, not_found }; + state st = not_found; + + // 1. small box + // 2. small value + // 3. any value + for (; k < lra.r_basis().size(); k++) { + j = lra.r_basis()[k]; + if (!column_is_int_inf(j)) + continue; + usage = lra.usage_in_terms(j); + if (is_boxed(j) && (new_range = lcs.m_r_upper_bounds()[j].x - lcs.m_r_lower_bounds()[j].x - rational(2*usage)) <= small_value) { + SASSERT(!is_fixed(j)); + if (st != small_box) { + n = 0; + st = small_box; + } + if (n == 0 || new_range < range) { + result = j; + range = new_range; + n = 1; + } + else if (new_range == range && (random() % (++n) == 0)) { + result = j; + } + continue; + } + if (st == small_box) + continue; + impq const& value = get_value(j); + if (abs(value.x) < small_value || + (has_upper(j) && small_value > upper_bound(j).x - value.x) || + (has_lower(j) && small_value > value.x - lower_bound(j).x)) { + if (st != is_small_value) { + n = 0; + st = is_small_value; + } + if (random() % (++n) == 0) + result = j; + } + if (st == is_small_value) + continue; + SASSERT(st == not_found || st == any_value); + st = any_value; + if (n == 0 /*|| usage > prev_usage*/) { + result = j; + prev_usage = usage; + n = 1; + } + else if (usage > 0 && /*usage == prev_usage && */ (random() % (++n) == 0)) + result = j; + } + + return result; +} + + } diff --git a/src/math/lp/int_solver.h b/src/math/lp/int_solver.h index c348f27f2..822e1cf1e 100644 --- a/src/math/lp/int_solver.h +++ b/src/math/lp/int_solver.h @@ -129,5 +129,8 @@ public: void find_feasible_solution(); lia_move hnf_cut(); void patch_nbasic_column(unsigned j) { m_patcher.patch_nbasic_column(j); } + + int select_int_infeasible_var(); + }; } diff --git a/src/smt/theory_arith_int.h b/src/smt/theory_arith_int.h index 699ebd5d2..7b76960dd 100644 --- a/src/smt/theory_arith_int.h +++ b/src/smt/theory_arith_int.h @@ -514,9 +514,11 @@ namespace smt { // SASSERT(m_value[x_i].is_rational()); // infinitesimals are not used for integer variables SASSERT(!m_value[x_i].is_int()); // the base variable is not assigned to an integer value. - if (constrain_free_vars(r) || !is_gomory_cut_target(r)) { + bool cfv = constrain_free_vars(r); + + if (cfv || !is_gomory_cut_target(r)) { TRACE("gomory_cut", tout << "failed to apply gomory cut:\n"; - tout << "constrain_free_vars(r): " << constrain_free_vars(r) << "\n";); + tout << "constrain_free_vars(r): " << cfv << "\n";); return false; }